21880944 has 120 divisors (see below), whose sum is σ = 64763712. Its totient is φ = 6888960.

The previous prime is 21880919. The next prime is 21880967. The reversal of 21880944 is 44908812.

It is a super-2 number, since 2×21880944² = 957551420662272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21880899 and 21880908.

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 23 ways as a sum of consecutive naturals, for example, 358674 + ... + 358734.

Almost surely, 2^21880944 is an apocalyptic number.

21880944 is a gapful number since it is divisible by the number (24) 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 21880944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32381856).

21880944 is an abundant number, since it is smaller than the sum of its proper divisors (42882768).

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

21880944 is a wasteful number, since it uses less digits than its factorization.

21880944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175 (or 166 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 21880944 is about 4677.7071306357. The cubic root of 21880944 is about 279.6975646056.

The spelling of 21880944 in words is "twenty-one million, eight hundred eighty thousand, nine hundred forty-four".