13531121520 has 80 divisors (see below), whose sum is σ = 47938836480. Its totient is φ = 3092827392.

The previous prime is 13531121509. The next prime is 13531121533. The reversal of 13531121520 is 2512113531.

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

It is a super-2 number, since 2×13531121520² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4025440 + ... + 4028799.

It is an arithmetic number, because the mean of its divisors is an integer number (599235456).

Almost surely, 2^13531121520 is an apocalyptic number.

13531121520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13531121520 is an abundant number, since it is smaller than the sum of its proper divisors (34407714960).

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

13531121520 is a wasteful number, since it uses less digits than its factorization.

13531121520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8054262 (or 8054256 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 24.

The spelling of 13531121520 in words is "thirteen billion, five hundred thirty-one million, one hundred twenty-one thousand, five hundred twenty".