21653235612 has 36 divisors (see below), whose sum is σ = 54786841200. Its totient is φ = 7210852032.

The previous prime is 21653235599. The next prime is 21653235619.

21653235612 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 3 + 2 + 35 + 612 = 666.

21653235612 is nontrivially palindromic in base 10.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-3 number, since 3×21653235612³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21653235619) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 248928 + ... + 324455.

It is an arithmetic number, because the mean of its divisors is an integer number (1521856700).

Almost surely, 2^21653235612 is an apocalyptic number.

It is an amenable number.

21653235612 is an abundant number, since it is smaller than the sum of its proper divisors (33133605588).

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

21653235612 is a wasteful number, since it uses less digits than its factorization.

21653235612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 574442 (or 574437 counting only the distinct ones).

The product of its digits is 64800, while the sum is 36.

The spelling of 21653235612 in words is "twenty-one billion, six hundred fifty-three million, two hundred thirty-five thousand, six hundred twelve".