21187541976 has 32 divisors (see below), whose sum is σ = 54677529600. Its totient is φ = 6834690720.

The previous prime is 21187541959. The next prime is 21187541981. The reversal of 21187541976 is 67914578112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14238196 + ... + 14239683.

It is an arithmetic number, because the mean of its divisors is an integer number (1708672800).

Almost surely, 2^21187541976 is an apocalyptic number.

It is an amenable number.

21187541976 is an abundant number, since it is smaller than the sum of its proper divisors (33489987624).

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

21187541976 is a wasteful number, since it uses less digits than its factorization.

21187541976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28477919 (or 28477915 counting only the distinct ones).

The product of its digits is 846720, while the sum is 51.

The spelling of 21187541976 in words is "twenty-one billion, one hundred eighty-seven million, five hundred forty-one thousand, nine hundred seventy-six".