21020628 has 12 divisors (see below), whose sum is σ = 49048160. Its totient is φ = 7006872.

The previous prime is 21020627. The next prime is 21020633. The reversal of 21020628 is 82602012.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020627) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 875848 + ... + 875871.

Almost surely, 2^21020628 is an apocalyptic number.

It is an amenable number.

21020628 is an abundant number, since it is smaller than the sum of its proper divisors (28027532).

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

21020628 is a wasteful number, since it uses less digits than its factorization.

21020628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1751726 (or 1751724 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21020628 is about 4584.8258418396. The cubic root of 21020628 is about 275.9827231361.

The spelling of 21020628 in words is "twenty-one million, twenty thousand, six hundred twenty-eight".