21613161878 has 16 divisors (see below), whose sum is σ = 40419419904. Its totient is φ = 8420712360.

The previous prime is 21613161863. The next prime is 21613161883. The reversal of 21613161878 is 87816131612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70172450 + ... + 70172757.

It is an arithmetic number, because the mean of its divisors is an integer number (2526213744).

Almost surely, 2^21613161878 is an apocalyptic number.

21613161878 is a deficient number, since it is larger than the sum of its proper divisors (18806258026).

21613161878 is a wasteful number, since it uses less digits than its factorization.

21613161878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140345227.

The product of its digits is 96768, while the sum is 44.

The spelling of 21613161878 in words is "twenty-one billion, six hundred thirteen million, one hundred sixty-one thousand, eight hundred seventy-eight".