21635644653612 has 96 divisors (see below), whose sum is σ = 61328008224000. Its totient is φ = 6541653888000.

The previous prime is 21635644653593. The next prime is 21635644653617.

21635644653612 is a `hidden beast` number, since 2 + 1 + 6 + 3 + 5 + 64 + 46 + 536 + 1 + 2 = 666.

21635644653612 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×21635644653612² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (21635644653617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19747014 + ... + 20813837.

It is an arithmetic number, because the mean of its divisors is an integer number (638833419000).

Almost surely, 2^{21635644653612} is an apocalyptic number.

21635644653612 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21635644653612 is an abundant number, since it is smaller than the sum of its proper divisors (39692363570388).

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

21635644653612 is a wasteful number, since it uses less digits than its factorization.

21635644653612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40561324 (or 40561316 counting only the distinct ones).

The product of its digits is 18662400, while the sum is 54.

The spelling of 21635644653612 in words is "twenty-one trillion, six hundred thirty-five billion, six hundred forty-four million, six hundred fifty-three thousand, six hundred twelve".