21691694078 has 8 divisors (see below), whose sum is σ = 32995816560. Its totient is φ = 10693088560.

The previous prime is 21691694027. The next prime is 21691694083. The reversal of 21691694078 is 87049619612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 76379063 + ... + 76379346.

It is an arithmetic number, because the mean of its divisors is an integer number (4124477070).

Almost surely, 2^21691694078 is an apocalyptic number.

21691694078 is a deficient number, since it is larger than the sum of its proper divisors (11304122482).

21691694078 is a wasteful number, since it uses less digits than its factorization.

21691694078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152758482.

The product of its (nonzero) digits is 1306368, while the sum is 53.

The spelling of 21691694078 in words is "twenty-one billion, six hundred ninety-one million, six hundred ninety-four thousand, seventy-eight".