21165331454 has 4 divisors (see below), whose sum is σ = 31747997184. Its totient is φ = 10582665726.

The previous prime is 21165331391. The next prime is 21165331487. The reversal of 21165331454 is 45413356112.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5291332862 + ... + 5291332865.

It is an arithmetic number, because the mean of its divisors is an integer number (7936999296).

Almost surely, 2^21165331454 is an apocalyptic number.

21165331454 is a deficient number, since it is larger than the sum of its proper divisors (10582665730).

21165331454 is a wasteful number, since it uses less digits than its factorization.

21165331454 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10582665729.

The product of its digits is 43200, while the sum is 35.

Adding to 21165331454 its reverse (45413356112), we get a palindrome (66578687566).

The spelling of 21165331454 in words is "twenty-one billion, one hundred sixty-five million, three hundred thirty-one thousand, four hundred fifty-four".