21991202880 has 56 divisors (see below), whose sum is σ = 69822072192. Its totient is φ = 5864320512.

The previous prime is 21991202879. The next prime is 21991202887. The reversal of 21991202880 is 8820219912.

It is a super-2 number, since 2×21991202880² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21991202887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11452792 + ... + 11454711.

Almost surely, 2^21991202880 is an apocalyptic number.

21991202880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21991202880 is an abundant number, since it is smaller than the sum of its proper divisors (47830869312).

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

21991202880 is a wasteful number, since it uses less digits than its factorization.

21991202880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22907523 (or 22907513 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 42.

The spelling of 21991202880 in words is "twenty-one billion, nine hundred ninety-one million, two hundred two thousand, eight hundred eighty".