1231220540 has 48 divisors (see below), whose sum is σ = 2825625600. Its totient is φ = 446921280.

The previous prime is 1231220531. The next prime is 1231220587. The reversal of 1231220540 is 450221321.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

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, 127109 + ... + 136451.

It is an arithmetic number, because the mean of its divisors is an integer number (58867200).

Almost surely, 2^1231220540 is an apocalyptic number.

1231220540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231220540 is an abundant number, since it is smaller than the sum of its proper divisors (1594405060).

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

1231220540 is a wasteful number, since it uses less digits than its factorization.

1231220540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9962 (or 9960 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 1231220540 is about 35088.7523289159. The cubic root of 1231220540 is about 1071.7955527818.

Adding to 1231220540 its reverse (450221321), we get a palindrome (1681441861).

The spelling of 1231220540 in words is "one billion, two hundred thirty-one million, two hundred twenty thousand, five hundred forty".