21662453891 has 8 divisors (see below), whose sum is σ = 23335764144. Its totient is φ = 19990139040.

The previous prime is 21662453867. The next prime is 21662453903. The reversal of 21662453891 is 19835426612.

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

It is a cyclic number.

It is not a de Polignac number, because 21662453891 - 2³⁴ = 4482584707 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21662453801) 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, 203336 + ... + 290981.

It is an arithmetic number, because the mean of its divisors is an integer number (2916970518).

Almost surely, 2^21662453891 is an apocalyptic number.

21662453891 is a deficient number, since it is larger than the sum of its proper divisors (1673310253).

21662453891 is a wasteful number, since it uses less digits than its factorization.

21662453891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 497701.

The product of its digits is 622080, while the sum is 47.

The spelling of 21662453891 in words is "twenty-one billion, six hundred sixty-two million, four hundred fifty-three thousand, eight hundred ninety-one".