21015624161 has 24 divisors (see below), whose sum is σ = 24778967040. Its totient is φ = 17769024000.

The previous prime is 21015624107. The next prime is 21015624163. The reversal of 21015624161 is 16142651012.

It is not a de Polignac number, because 21015624161 - 2²⁶ = 20948515297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21015624163) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 6195776 + ... + 6199166.

It is an arithmetic number, because the mean of its divisors is an integer number (1032456960).

Almost surely, 2^21015624161 is an apocalyptic number.

It is an amenable number.

21015624161 is a deficient number, since it is larger than the sum of its proper divisors (3763342879).

21015624161 is a wasteful number, since it uses less digits than its factorization.

21015624161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5085 (or 5078 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The spelling of 21015624161 in words is "twenty-one billion, fifteen million, six hundred twenty-four thousand, one hundred sixty-one".