1231536720 has 80 divisors (see below), whose sum is σ = 3841307712. Its totient is φ = 326384640.

The previous prime is 1231536637. The next prime is 1231536739. The reversal of 1231536720 is 276351321.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23380 + ... + 54860.

Almost surely, 2^1231536720 is an apocalyptic number.

1231536720 is a gapful number since it is divisible by the number (10) 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 1231536720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1920653856).

1231536720 is an abundant number, since it is smaller than the sum of its proper divisors (2609770992).

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

1231536720 is a wasteful number, since it uses less digits than its factorization.

1231536720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31660 (or 31654 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 1231536720 is about 35093.2574720558. The cubic root of 1231536720 is about 1071.8872913731.

The spelling of 1231536720 in words is "one billion, two hundred thirty-one million, five hundred thirty-six thousand, seven hundred twenty".