21879582 has 16 divisors (see below), whose sum is σ = 44251920. Its totient is φ = 7211072.

The previous prime is 21879577. The next prime is 21879593. The reversal of 21879582 is 28597812.

It is a super-2 number, since 2×21879582² = 957432216989448, which contains 22 as substring.

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, 19953 + ... + 21020.

It is an arithmetic number, because the mean of its divisors is an integer number (2765745).

Almost surely, 2^21879582 is an apocalyptic number.

21879582 is an abundant number, since it is smaller than the sum of its proper divisors (22372338).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21879582 is a wasteful number, since it uses less digits than its factorization.

21879582 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41067.

The product of its digits is 80640, while the sum is 42.

The square root of 21879582 is about 4677.5615442237. The cubic root of 21879582 is about 279.6917611390.

It can be divided in two parts, 218 and 79582, that added together give a triangular number (79800 = T₃₉₉).

The spelling of 21879582 in words is "twenty-one million, eight hundred seventy-nine thousand, five hundred eighty-two".