21879936 has 128 divisors (see below), whose sum is σ = 69686400. Its totient is φ = 6718464.

The previous prime is 21879929. The next prime is 21879943. The reversal of 21879936 is 63997812.

It is an interprime number because it is at equal distance from previous prime (21879929) and next prime (21879943).

It is a tau number, because it is divible by the number of its divisors (128).

It is a junction number, because it is equal to n+sod(n) for n = 21879891 and 21879900.

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, 44685 + ... + 45171.

It is an arithmetic number, because the mean of its divisors is an integer number (544425).

Almost surely, 2^21879936 is an apocalyptic number.

21879936 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21879936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34843200).

21879936 is an abundant number, since it is smaller than the sum of its proper divisors (47806464).

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

21879936 is a wasteful number, since it uses less digits than its factorization.

21879936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523 (or 505 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 21879936 is about 4677.5993842996. The cubic root of 21879936 is about 279.6932695521.

The spelling of 21879936 in words is "twenty-one million, eight hundred seventy-nine thousand, nine hundred thirty-six".