21638683612 has 144 divisors (see below), whose sum is σ = 49289076480. Its totient is φ = 8279107200.

The previous prime is 21638683603. The next prime is 21638683639.

21638683612 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13348162 + ... + 13349782.

Almost surely, 2^21638683612 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21638683612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24644538240).

21638683612 is an abundant number, since it is smaller than the sum of its proper divisors (27650392868).

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

21638683612 is a wasteful number, since it uses less digits than its factorization.

21638683612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1709 (or 1674 counting only the distinct ones).

The product of its digits is 497664, while the sum is 46.

The spelling of 21638683612 in words is "twenty-one billion, six hundred thirty-eight million, six hundred eighty-three thousand, six hundred twelve".