21051628 has 24 divisors (see below), whose sum is σ = 39799760. Its totient is φ = 9685440.

The previous prime is 21051623. The next prime is 21051637. The reversal of 21051628 is 82615012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051623) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 29338 + ... + 30046.

Almost surely, 2^21051628 is an apocalyptic number.

It is an amenable number.

21051628 is a deficient number, since it is larger than the sum of its proper divisors (18748132).

21051628 is a wasteful number, since it uses less digits than its factorization.

21051628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1297 (or 1295 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 21051628 is about 4588.2053136275. The cubic root of 21051628 is about 276.1183242571.

The spelling of 21051628 in words is "twenty-one million, fifty-one thousand, six hundred twenty-eight".