21331563613 has 4 divisors (see below), whose sum is σ = 21438757600. Its totient is φ = 21224369628.

The previous prime is 21331563593. The next prime is 21331563629. The reversal of 21331563613 is 31636513312.

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 21331563613 - 2⁹ = 21331563101 is a prime.

It is a super-2 number, since 2×21331563613² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331563313) 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, 53596695 + ... + 53597092.

It is an arithmetic number, because the mean of its divisors is an integer number (5359689400).

Almost surely, 2^21331563613 is an apocalyptic number.

It is an amenable number.

21331563613 is a deficient number, since it is larger than the sum of its proper divisors (107193987).

21331563613 is a wasteful number, since it uses less digits than its factorization.

21331563613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107193986.

The product of its digits is 29160, while the sum is 34.

The spelling of 21331563613 in words is "twenty-one billion, three hundred thirty-one million, five hundred sixty-three thousand, six hundred thirteen".