21621533363 has 4 divisors (see below), whose sum is σ = 21786583368. Its totient is φ = 21456483360.

The previous prime is 21621533359. The next prime is 21621533371. The reversal of 21621533363 is 36333512612.

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

It is a cyclic number.

It is not a de Polignac number, because 21621533363 - 2² = 21621533359 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21621533383) 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, 82524806 + ... + 82525067.

It is an arithmetic number, because the mean of its divisors is an integer number (5446645842).

Almost surely, 2^21621533363 is an apocalyptic number.

21621533363 is a deficient number, since it is larger than the sum of its proper divisors (165050005).

21621533363 is a wasteful number, since it uses less digits than its factorization.

21621533363 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165050004.

The product of its digits is 58320, while the sum is 35.

The spelling of 21621533363 in words is "twenty-one billion, six hundred twenty-one million, five hundred thirty-three thousand, three hundred sixty-three".