21191958880 has 24 divisors (see below), whose sum is σ = 50066003232. Its totient is φ = 8476783488.

The previous prime is 21191958877. The next prime is 21191958929. The reversal of 21191958880 is 8885919112.

It is a happy number.

It is a super-2 number, since 2×21191958880² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (52) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66224712 + ... + 66225031.

It is an arithmetic number, because the mean of its divisors is an integer number (2086083468).

Almost surely, 2^21191958880 is an apocalyptic number.

21191958880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21191958880 is an abundant number, since it is smaller than the sum of its proper divisors (28874044352).

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

21191958880 is a wasteful number, since it uses less digits than its factorization.

21191958880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132449758 (or 132449750 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 52.

The spelling of 21191958880 in words is "twenty-one billion, one hundred ninety-one million, nine hundred fifty-eight thousand, eight hundred eighty".