21376765403281 has 2 divisors, whose sum is σ = 21376765403282. Its totient is φ = 21376765403280.

The previous prime is 21376765403263. The next prime is 21376765403309. The reversal of 21376765403281 is 18230456767312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21367552475025 + 9212928256 = 4622505^2 + 95984^2 .

It is a cyclic number.

It is not a de Polignac number, because 21376765403281 - 2²³ = 21376757014673 is a prime.

It is a super-2 number, since 2×21376765403281² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21376765401281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10688382701640 + 10688382701641.

It is an arithmetic number, because the mean of its divisors is an integer number (10688382701641).

Almost surely, 2^{21376765403281} is an apocalyptic number.

It is an amenable number.

21376765403281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21376765403281 is an equidigital number, since it uses as much as digits as its factorization.

21376765403281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10160640, while the sum is 55.

The spelling of 21376765403281 in words is "twenty-one trillion, three hundred seventy-six billion, seven hundred sixty-five million, four hundred three thousand, two hundred eighty-one".