21120164436 has 36 divisors (see below), whose sum is σ = 57326162208. Its totient is φ = 6034332528.

The previous prime is 21120164413. The next prime is 21120164441. The reversal of 21120164436 is 63446102112.

It is a super-2 number, since 2×21120164436² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17958736 + ... + 17959911.

Almost surely, 2^21120164436 is an apocalyptic number.

It is an amenable number.

21120164436 is an abundant number, since it is smaller than the sum of its proper divisors (36205997772).

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

21120164436 is a wasteful number, since it uses less digits than its factorization.

21120164436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35918668 (or 35918659 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

Adding to 21120164436 its reverse (63446102112), we get a palindrome (84566266548).

The spelling of 21120164436 in words is "twenty-one billion, one hundred twenty million, one hundred sixty-four thousand, four hundred thirty-six".