21052668 has 72 divisors (see below), whose sum is σ = 60832128. Its totient is φ = 5548608.

The previous prime is 21052651. The next prime is 21052679. The reversal of 21052668 is 86625012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13455 + ... + 14937.

Almost surely, 2^21052668 is an apocalyptic number.

21052668 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21052668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30416064).

21052668 is an abundant number, since it is smaller than the sum of its proper divisors (39779460).

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

21052668 is a wasteful number, since it uses less digits than its factorization.

21052668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1523 (or 1508 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 21052668 is about 4588.3186463017. The cubic root of 21052668 is about 276.1228711474.

The spelling of 21052668 in words is "twenty-one million, fifty-two thousand, six hundred sixty-eight".