21057070 has 16 divisors (see below), whose sum is σ = 38927808. Its totient is φ = 8195040.

The previous prime is 21057061. The next prime is 21057083. The reversal of 21057070 is 7075012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28086 + ... + 28825.

It is an arithmetic number, because the mean of its divisors is an integer number (2432988).

Almost surely, 2^21057070 is an apocalyptic number.

21057070 is a deficient number, since it is larger than the sum of its proper divisors (17870738).

21057070 is a wasteful number, since it uses less digits than its factorization.

21057070 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56955.

The product of its (nonzero) digits is 490, while the sum is 22.

The square root of 21057070 is about 4588.7983176426. The cubic root of 21057070 is about 276.1421150768.

The spelling of 21057070 in words is "twenty-one million, fifty-seven thousand, seventy".