1231516656 has 80 divisors (see below), whose sum is σ = 3571472800. Its totient is φ = 406259712.

The previous prime is 1231516651. The next prime is 1231516661. The reversal of 1231516656 is 6566151321.

It is an interprime number because it is at equal distance from previous prime (1231516651) and next prime (1231516661).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 1231516656.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231516651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27210 + ... + 56598.

It is an arithmetic number, because the mean of its divisors is an integer number (44643410).

Almost surely, 2^1231516656 is an apocalyptic number.

1231516656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1231516656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1785736400).

1231516656 is an abundant number, since it is smaller than the sum of its proper divisors (2339956144).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1231516656 is a wasteful number, since it uses less digits than its factorization.

1231516656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29503 (or 29491 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 1231516656 is about 35092.9716040121. The cubic root of 1231516656 is about 1071.8814703358.

Adding to 1231516656 its reverse (6566151321), we get a palindrome (7797667977).

The spelling of 1231516656 in words is "one billion, two hundred thirty-one million, five hundred sixteen thousand, six hundred fifty-six".