11813721520 has 20 divisors (see below), whose sum is σ = 27466902720. Its totient is φ = 4725488576.

The previous prime is 11813721463. The next prime is 11813721539. The reversal of 11813721520 is 2512731811.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×11813721520² (a number of 21 digits) contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 73835680 + ... + 73835839.

It is an arithmetic number, because the mean of its divisors is an integer number (1373345136).

Almost surely, 2^11813721520 is an apocalyptic number.

11813721520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

11813721520 is an abundant number, since it is smaller than the sum of its proper divisors (15653181200).

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

11813721520 is a wasteful number, since it uses less digits than its factorization.

11813721520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147671532 (or 147671526 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 31.

The spelling of 11813721520 in words is "eleven billion, eight hundred thirteen million, seven hundred twenty-one thousand, five hundred twenty".