21515950974 has 16 divisors (see below), whose sum is σ = 49179316608. Its totient is φ = 6147414552.

The previous prime is 21515950961. The next prime is 21515950991. The reversal of 21515950974 is 47905951512.

It is a super-2 number, since 2×21515950974² (a number of 21 digits) contains 22 as substring.

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, 256142232 + ... + 256142315.

It is an arithmetic number, because the mean of its divisors is an integer number (3073707288).

Almost surely, 2^21515950974 is an apocalyptic number.

21515950974 is an abundant number, since it is smaller than the sum of its proper divisors (27663365634).

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

21515950974 is a wasteful number, since it uses less digits than its factorization.

21515950974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512284559.

The product of its (nonzero) digits is 567000, while the sum is 48.

The spelling of 21515950974 in words is "twenty-one billion, five hundred fifteen million, nine hundred fifty thousand, nine hundred seventy-four".