21451032164 has 12 divisors (see below), whose sum is σ = 37540456044. Its totient is φ = 10725187584.

The previous prime is 21451032151. The next prime is 21451032181. The reversal of 21451032164 is 46123015412.

It can be written as a sum of positive squares in 2 ways, for example, as 21219748900 + 231283264 = 145670^2 + 15208^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120164 + ... + 239460.

It is an arithmetic number, because the mean of its divisors is an integer number (3128371337).

Almost surely, 2^21451032164 is an apocalyptic number.

It is an amenable number.

21451032164 is a deficient number, since it is larger than the sum of its proper divisors (16089423880).

21451032164 is a wasteful number, since it uses less digits than its factorization.

21451032164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164254 (or 164252 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

Adding to 21451032164 its reverse (46123015412), we get a palindrome (67574047576).

The spelling of 21451032164 in words is "twenty-one billion, four hundred fifty-one million, thirty-two thousand, one hundred sixty-four".