21879718 has 16 divisors (see below), whose sum is σ = 37569024. Its totient is φ = 9361800.

The previous prime is 21879709. The next prime is 21879743. The reversal of 21879718 is 81797812.

It is a happy number.

It is a congruent number.

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, 13971 + ... + 15457.

It is an arithmetic number, because the mean of its divisors is an integer number (2348064).

Almost surely, 2^21879718 is an apocalyptic number.

21879718 is a deficient number, since it is larger than the sum of its proper divisors (15689306).

21879718 is a wasteful number, since it uses less digits than its factorization.

21879718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2547.

The product of its digits is 56448, while the sum is 43.

The square root of 21879718 is about 4677.5760816902. The cubic root of 21879718 is about 279.6923406442.

The spelling of 21879718 in words is "twenty-one million, eight hundred seventy-nine thousand, seven hundred eighteen".