21028570 has 8 divisors (see below), whose sum is σ = 37851444. Its totient is φ = 8411424.

The previous prime is 21028549. The next prime is 21028597. The reversal of 21028570 is 7582012.

It can be written as a sum of positive squares in 2 ways, for example, as 20711601 + 316969 = 4551^2 + 563^2 .

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

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 3 ways as a sum of consecutive naturals, for example, 1051419 + ... + 1051438.

Almost surely, 2^21028570 is an apocalyptic number.

21028570 is a deficient number, since it is larger than the sum of its proper divisors (16822874).

21028570 is a wasteful number, since it uses less digits than its factorization.

21028570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2102864.

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 21028570 is about 4585.6918780049. The cubic root of 21028570 is about 276.0174759641.

The spelling of 21028570 in words is "twenty-one million, twenty-eight thousand, five hundred seventy".