21800664691 has 8 divisors (see below), whose sum is σ = 23492720160. Its totient is φ = 20110763712.

The previous prime is 21800664623. The next prime is 21800664749. The reversal of 21800664691 is 19646600812.

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

It is not a de Polignac number, because 21800664691 - 2³¹ = 19653181043 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21800664091) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 517570 + ... + 558103.

It is an arithmetic number, because the mean of its divisors is an integer number (2936590020).

Almost surely, 2^21800664691 is an apocalyptic number.

21800664691 is a deficient number, since it is larger than the sum of its proper divisors (1692055469).

21800664691 is a wasteful number, since it uses less digits than its factorization.

21800664691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1077245.

The product of its (nonzero) digits is 124416, while the sum is 43.

The spelling of 21800664691 in words is "twenty-one billion, eight hundred million, six hundred sixty-four thousand, six hundred ninety-one".