21057510 has 32 divisors (see below), whose sum is σ = 53199360. Its totient is φ = 5319648.

The previous prime is 21057503. The next prime is 21057511. The reversal of 21057510 is 1575012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21057511) 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 15 ways as a sum of consecutive naturals, for example, 17902 + ... + 19041.

It is an arithmetic number, because the mean of its divisors is an integer number (1662480).

Almost surely, 2^21057510 is an apocalyptic number.

21057510 is an abundant number, since it is smaller than the sum of its proper divisors (32141850).

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

21057510 is a wasteful number, since it uses less digits than its factorization.

21057510 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36972.

The product of its (nonzero) digits is 350, while the sum is 21.

The square root of 21057510 is about 4588.8462602271. The cubic root of 21057510 is about 276.1440384480.

The spelling of 21057510 in words is "twenty-one million, fifty-seven thousand, five hundred ten".