21062864 has 40 divisors (see below), whose sum is σ = 43532928. Its totient is φ = 9838080.

The previous prime is 21062851. The next prime is 21062869. The reversal of 21062864 is 46826012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21062869) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57209 + ... + 57575.

Almost surely, 2^21062864 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 21062864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21766464).

21062864 is an abundant number, since it is smaller than the sum of its proper divisors (22470064).

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

21062864 is a wasteful number, since it uses less digits than its factorization.

21062864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 603 (or 597 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 21062864 is about 4589.4295941871. The cubic root of 21062864 is about 276.1674402319.

Adding to 21062864 its reverse (46826012), we get a palindrome (67888876).

The spelling of 21062864 in words is "twenty-one million, sixty-two thousand, eight hundred sixty-four".