21916987308 has 36 divisors (see below), whose sum is σ = 55579441008. Its totient is φ = 7282167840.

The previous prime is 21916987277. The next prime is 21916987327. The reversal of 21916987308 is 80378961912.

It is a tau number, because it is divible by the number of its divisors (36).

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 11 ways as a sum of consecutive naturals, for example, 967591 + ... + 989982.

Almost surely, 2^21916987308 is an apocalyptic number.

It is an amenable number.

21916987308 is an abundant number, since it is smaller than the sum of its proper divisors (33662453700).

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

21916987308 is a wasteful number, since it uses less digits than its factorization.

21916987308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1957894 (or 1957889 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 54.

The spelling of 21916987308 in words is "twenty-one billion, nine hundred sixteen million, nine hundred eighty-seven thousand, three hundred eight".