21231330961 has 2 divisors, whose sum is σ = 21231330962. Its totient is φ = 21231330960.

The previous prime is 21231330947. The next prime is 21231330971. The reversal of 21231330961 is 16903313212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18685523025 + 2545807936 = 136695^2 + 50456^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231330961 - 2⁷ = 21231330833 is a prime.

It is not a weakly prime, because it can be changed into another prime (21231330971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615665480 + 10615665481.

It is an arithmetic number, because the mean of its divisors is an integer number (10615665481).

Almost surely, 2^21231330961 is an apocalyptic number.

It is an amenable number.

21231330961 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231330961 is an equidigital number, since it uses as much as digits as its factorization.

21231330961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 31.

The spelling of 21231330961 in words is "twenty-one billion, two hundred thirty-one million, three hundred thirty thousand, nine hundred sixty-one".