21130864 has 20 divisors (see below), whose sum is σ = 43349904. Its totient is φ = 9943808.

The previous prime is 21130853. The next prime is 21130877. The reversal of 21130864 is 46803112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38572 + ... + 39115.

Almost surely, 2^21130864 is an apocalyptic number.

It is an amenable number.

21130864 is an abundant number, since it is smaller than the sum of its proper divisors (22219040).

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

21130864 is a wasteful number, since it uses less digits than its factorization.

21130864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77712 (or 77706 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 21130864 is about 4596.8319525517. The cubic root of 21130864 is about 276.4643168071.

Adding to 21130864 its reverse (46803112), we get a palindrome (67933976).

The spelling of 21130864 in words is "twenty-one million, one hundred thirty thousand, eight hundred sixty-four".