21990391716 has 24 divisors (see below), whose sum is σ = 51319850400. Its totient is φ = 7328853952.

The previous prime is 21990391699. The next prime is 21990391733. The reversal of 21990391716 is 61719309912.

It is an interprime number because it is at equal distance from previous prime (21990391699) and next prime (21990391733).

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86466 + ... + 226841.

It is an arithmetic number, because the mean of its divisors is an integer number (2138327100).

Almost surely, 2^21990391716 is an apocalyptic number.

It is an amenable number.

21990391716 is an abundant number, since it is smaller than the sum of its proper divisors (29329458684).

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

21990391716 is a wasteful number, since it uses less digits than its factorization.

21990391716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319163 (or 319161 counting only the distinct ones).

The product of its (nonzero) digits is 183708, while the sum is 48.

The spelling of 21990391716 in words is "twenty-one billion, nine hundred ninety million, three hundred ninety-one thousand, seven hundred sixteen".