21256070 has 32 divisors (see below), whose sum is σ = 42110496. Its totient is φ = 7724640.

The previous prime is 21256057. The next prime is 21256087. The reversal of 21256070 is 7065212.

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 15 ways as a sum of consecutive naturals, for example, 12512 + ... + 14108.

It is an arithmetic number, because the mean of its divisors is an integer number (1315953).

Almost surely, 2^21256070 is an apocalyptic number.

21256070 is a deficient number, since it is larger than the sum of its proper divisors (20854426).

21256070 is a wasteful number, since it uses less digits than its factorization.

21256070 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1637 (or 1615 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21256070 is about 4610.4305655763. The cubic root of 21256070 is about 277.0092834451.

The spelling of 21256070 in words is "twenty-one million, two hundred fifty-six thousand, seventy".