21602811646538 has 32 divisors (see below), whose sum is σ = 33138525563712. Its totient is φ = 10558167984000.

The previous prime is 21602811646531. The next prime is 21602811646567. The reversal of 21602811646538 is 83564611820612.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a self number, because there is not a number n which added to its sum of digits gives 21602811646538.

It is not an unprimeable number, because it can be changed into a prime (21602811646531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 165853838 + ... + 165984038.

It is an arithmetic number, because the mean of its divisors is an integer number (1035578923866).

Almost surely, 2^{21602811646538} is an apocalyptic number.

21602811646538 is a deficient number, since it is larger than the sum of its proper divisors (11535713917174).

21602811646538 is a wasteful number, since it uses less digits than its factorization.

21602811646538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136070.

The product of its (nonzero) digits is 3317760, while the sum is 53.

The spelling of 21602811646538 in words is "twenty-one trillion, six hundred two billion, eight hundred eleven million, six hundred forty-six thousand, five hundred thirty-eight".