21917804880 has 80 divisors (see below), whose sum is σ = 71941984704. Its totient is φ = 5500938240.

The previous prime is 21917804873. The next prime is 21917804891. The reversal of 21917804880 is 8840871912.

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

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2681926 + ... + 2690085.

Almost surely, 2^21917804880 is an apocalyptic number.

21917804880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21917804880 is an abundant number, since it is smaller than the sum of its proper divisors (50024179824).

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

21917804880 is a wasteful number, since it uses less digits than its factorization.

21917804880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5372044 (or 5372038 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 48.

The spelling of 21917804880 in words is "twenty-one billion, nine hundred seventeen million, eight hundred four thousand, eight hundred eighty".