21057370 has 16 divisors (see below), whose sum is σ = 39126528. Its totient is φ = 8151120.

The previous prime is 21057341. The next prime is 21057419. The reversal of 21057370 is 7375012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33654 + ... + 34273.

It is an arithmetic number, because the mean of its divisors is an integer number (2445408).

Almost surely, 2^21057370 is an apocalyptic number.

21057370 is a deficient number, since it is larger than the sum of its proper divisors (18069158).

21057370 is a wasteful number, since it uses less digits than its factorization.

21057370 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67965.

The product of its (nonzero) digits is 1470, while the sum is 25.

The square root of 21057370 is about 4588.8310058227. The cubic root of 21057370 is about 276.1434264691.

The spelling of 21057370 in words is "twenty-one million, fifty-seven thousand, three hundred seventy".