21664089357 has 4 divisors (see below), whose sum is σ = 28885452480. Its totient is φ = 14442726236.

The previous prime is 21664089329. The next prime is 21664089361. The reversal of 21664089357 is 75398046612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21664089357 - 2¹⁰ = 21664088333 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21664089257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3610681557 + ... + 3610681562.

It is an arithmetic number, because the mean of its divisors is an integer number (7221363120).

It is a 1-persistent number, because it is pandigital, but 2⋅21664089357 = 43328178714 is not.

Almost surely, 2^21664089357 is an apocalyptic number.

It is an amenable number.

21664089357 is a deficient number, since it is larger than the sum of its proper divisors (7221363123).

21664089357 is an equidigital number, since it uses as much as digits as its factorization.

21664089357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7221363122.

The product of its (nonzero) digits is 2177280, while the sum is 51.

The spelling of 21664089357 in words is "twenty-one billion, six hundred sixty-four million, eighty-nine thousand, three hundred fifty-seven".