21028790 has 8 divisors (see below), whose sum is σ = 37851840. Its totient is φ = 8411512.

The previous prime is 21028771. The next prime is 21028823. The reversal of 21028790 is 9782012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1051430 + ... + 1051449.

It is an arithmetic number, because the mean of its divisors is an integer number (4731480).

Almost surely, 2^21028790 is an apocalyptic number.

21028790 is a deficient number, since it is larger than the sum of its proper divisors (16823050).

21028790 is a wasteful number, since it uses less digits than its factorization.

21028790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2102886.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 21028790 is about 4585.7158655983. The cubic root of 21028790 is about 276.0184385217.

The spelling of 21028790 in words is "twenty-one million, twenty-eight thousand, seven hundred ninety".