21798400164 has 24 divisors (see below), whose sum is σ = 51506770560. Its totient is φ = 7174156704.

The previous prime is 21798400153. The next prime is 21798400193. The reversal of 21798400164 is 46100489712.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11496099 + ... + 11497994.

It is an arithmetic number, because the mean of its divisors is an integer number (2146115440).

Almost surely, 2^21798400164 is an apocalyptic number.

It is an amenable number.

21798400164 is an abundant number, since it is smaller than the sum of its proper divisors (29708370396).

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

21798400164 is a wasteful number, since it uses less digits than its factorization.

21798400164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22994179 (or 22994177 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 42.

Adding to 21798400164 its reverse (46100489712), we get a palindrome (67898889876).

The spelling of 21798400164 in words is "twenty-one billion, seven hundred ninety-eight million, four hundred thousand, one hundred sixty-four".