21776880 has 80 divisors (see below), whose sum is σ = 69709824. Its totient is φ = 5617920.

The previous prime is 21776857. The next prime is 21776891. The reversal of 21776880 is 8867712.

It is a tau number, because it is divible by the number of its divisors (80).

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 15 ways as a sum of consecutive naturals, for example, 5977 + ... + 8903.

Almost surely, 2^21776880 is an apocalyptic number.

21776880 is a gapful number since it is divisible by the number (20) 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 21776880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34854912).

21776880 is an abundant number, since it is smaller than the sum of its proper divisors (47932944).

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

21776880 is a wasteful number, since it uses less digits than its factorization.

21776880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2974 (or 2968 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 39.

The square root of 21776880 is about 4666.5704751991. The cubic root of 21776880 is about 279.2534534755.

The spelling of 21776880 in words is "twenty-one million, seven hundred seventy-six thousand, eight hundred eighty".