21915415678 has 32 divisors (see below), whose sum is σ = 35960311296. Its totient is φ = 9956422368.

The previous prime is 21915415637. The next prime is 21915415693. The reversal of 21915415678 is 87651451912.

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 15 ways as a sum of consecutive naturals, for example, 422725 + ... + 471727.

It is an arithmetic number, because the mean of its divisors is an integer number (1123759728).

Almost surely, 2^21915415678 is an apocalyptic number.

21915415678 is a deficient number, since it is larger than the sum of its proper divisors (14044895618).

21915415678 is a wasteful number, since it uses less digits than its factorization.

21915415678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49288.

The product of its digits is 604800, while the sum is 49.

The spelling of 21915415678 in words is "twenty-one billion, nine hundred fifteen million, four hundred fifteen thousand, six hundred seventy-eight".