21602764861821 has 48 divisors (see below), whose sum is σ = 36947893032960. Its totient is φ = 11990301644160.

The previous prime is 21602764861819. The next prime is 21602764861903. The reversal of 21602764861821 is 12816846720612.

21602764861821 is a `hidden beast` number, since 2 + 1 + 60 + 2 + 76 + 486 + 18 + 21 = 666.

It is not a de Polignac number, because 21602764861821 - 2¹ = 21602764861819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21602764868821) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 65920666 + ... + 66247563.

It is an arithmetic number, because the mean of its divisors is an integer number (769747771520).

Almost surely, 2^{21602764861821} is an apocalyptic number.

It is an amenable number.

21602764861821 is a deficient number, since it is larger than the sum of its proper divisors (15345128171139).

21602764861821 is a wasteful number, since it uses less digits than its factorization.

21602764861821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132168386 (or 132168383 counting only the distinct ones).

The product of its (nonzero) digits is 3096576, while the sum is 54.

The spelling of 21602764861821 in words is "twenty-one trillion, six hundred two billion, seven hundred sixty-four million, eight hundred sixty-one thousand, eight hundred twenty-one".