21303506961 has 36 divisors (see below), whose sum is σ = 33861047220. Its totient is φ = 12896875200.

The previous prime is 21303506953. The next prime is 21303506963. The reversal of 21303506961 is 16960530312.

21303506961 is a `hidden beast` number, since 213 + 0 + 350 + 6 + 96 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 16292990736 + 5010516225 = 127644^2 + 70785^2 .

It is not a de Polignac number, because 21303506961 - 2³ = 21303506953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21303506963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1014355 + ... + 1035143.

It is an arithmetic number, because the mean of its divisors is an integer number (940584645).

Almost surely, 2^21303506961 is an apocalyptic number.

It is an amenable number.

21303506961 is a deficient number, since it is larger than the sum of its proper divisors (12557540259).

21303506961 is a wasteful number, since it uses less digits than its factorization.

21303506961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21758 (or 21744 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 36.

The spelling of 21303506961 in words is "twenty-one billion, three hundred three million, five hundred six thousand, nine hundred sixty-one".