11956521720 has 256 divisors, whose sum is σ = 42245038080. Its totient is φ = 2668953600.

The previous prime is 11956521677. The next prime is 11956521727. The reversal of 11956521720 is 2712565911.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11956521727) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 10999017 + ... + 11000103.

It is an arithmetic number, because the mean of its divisors is an integer number (165019680).

Almost surely, 2^11956521720 is an apocalyptic number.

11956521720 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 11956521720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21122519040).

11956521720 is an abundant number, since it is smaller than the sum of its proper divisors (30288516360).

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

11956521720 is a wasteful number, since it uses less digits than its factorization.

11956521720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1766 (or 1762 counting only the distinct ones).

The product of its (nonzero) digits is 37800, while the sum is 39.

The spelling of 11956521720 in words is "eleven billion, nine hundred fifty-six million, five hundred twenty-one thousand, seven hundred twenty".