21659974 has 32 divisors (see below), whose sum is σ = 39108096. Its totient is φ = 8796480.

The previous prime is 21659969. The next prime is 21659993. The reversal of 21659974 is 47995612.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21659974.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43869 + ... + 44359.

It is an arithmetic number, because the mean of its divisors is an integer number (1222128).

Almost surely, 2^21659974 is an apocalyptic number.

21659974 is a deficient number, since it is larger than the sum of its proper divisors (17448122).

21659974 is a wasteful number, since it uses less digits than its factorization.

21659974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660.

The product of its digits is 136080, while the sum is 43.

The square root of 21659974 is about 4654.0277180094. The cubic root of 21659974 is about 278.7528461305.

The spelling of 21659974 in words is "twenty-one million, six hundred fifty-nine thousand, nine hundred seventy-four".