645960468281 has 2 divisors, whose sum is σ = 645960468282. Its totient is φ = 645960468280.

The previous prime is 645960468233. The next prime is 645960468313. The reversal of 645960468281 is 182864069546.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 644582573881 + 1377894400 = 802859^2 + 37120^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645960468281 is a prime.

It is a super-2 number, since 2×645960468281² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 645960468281.

It is not a weakly prime, because it can be changed into another prime (645960467281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322980234140 + 322980234141.

It is an arithmetic number, because the mean of its divisors is an integer number (322980234141).

Almost surely, 2^645960468281 is an apocalyptic number.

It is an amenable number.

645960468281 is a deficient number, since it is larger than the sum of its proper divisors (1).

645960468281 is an equidigital number, since it uses as much as digits as its factorization.

645960468281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19906560, while the sum is 59.

The spelling of 645960468281 in words is "six hundred forty-five billion, nine hundred sixty million, four hundred sixty-eight thousand, two hundred eighty-one".