21312131102981 has 2 divisors, whose sum is σ = 21312131102982. Its totient is φ = 21312131102980.

The previous prime is 21312131102923. The next prime is 21312131103013. The reversal of 21312131102981 is 18920113121312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15553235050081 + 5758896052900 = 3943759^2 + 2399770^2 .

It is a cyclic number.

It is not a de Polignac number, because 21312131102981 - 2³⁰ = 21311057361157 is a prime.

It is a super-2 number, since 2×21312131102981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21312131102681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656065551490 + 10656065551491.

It is an arithmetic number, because the mean of its divisors is an integer number (10656065551491).

Almost surely, 2^{21312131102981} is an apocalyptic number.

It is an amenable number.

21312131102981 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312131102981 is an equidigital number, since it uses as much as digits as its factorization.

21312131102981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 35.

The spelling of 21312131102981 in words is "twenty-one trillion, three hundred twelve billion, one hundred thirty-one million, one hundred two thousand, nine hundred eighty-one".