21089816694 has 16 divisors (see below), whose sum is σ = 46866259440. Its totient is φ = 7029938880.

The previous prime is 21089816623. The next prime is 21089816749. The reversal of 21089816694 is 49661898012.

It is a Harshad number since it is a multiple of its sum of digits (54), and also a Moran number because the ratio is a prime number: 390552161 = 21089816694 / (2 + 1 + 0 + 8 + 9 + 8 + 1 + 6 + 6 + 9 + 4).

It is a self number, because there is not a number n which added to its sum of digits gives 21089816694.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195276027 + ... + 195276134.

It is an arithmetic number, because the mean of its divisors is an integer number (2929141215).

Almost surely, 2^21089816694 is an apocalyptic number.

21089816694 is an abundant number, since it is smaller than the sum of its proper divisors (25776442746).

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

21089816694 is a wasteful number, since it uses less digits than its factorization.

21089816694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390552172 (or 390552166 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 54.

The spelling of 21089816694 in words is "twenty-one billion, eighty-nine million, eight hundred sixteen thousand, six hundred ninety-four".