21951081916 has 24 divisors (see below), whose sum is σ = 38604777120. Its totient is φ = 10921208832.

The previous prime is 21951081907. The next prime is 21951081947. The reversal of 21951081916 is 61918015912.

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, 1574665 + ... + 1588543.

It is an arithmetic number, because the mean of its divisors is an integer number (1608532380).

Almost surely, 2^21951081916 is an apocalyptic number.

It is an amenable number.

21951081916 is a deficient number, since it is larger than the sum of its proper divisors (16653695204).

21951081916 is a wasteful number, since it uses less digits than its factorization.

21951081916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15813 (or 15811 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 43.

The spelling of 21951081916 in words is "twenty-one billion, nine hundred fifty-one million, eighty-one thousand, nine hundred sixteen".