645635242481 has 2 divisors, whose sum is σ = 645635242482. Its totient is φ = 645635242480.

The previous prime is 645635242457. The next prime is 645635242487. The reversal of 645635242481 is 184242536546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 434862432481 + 210772810000 = 659441^2 + 459100^2 .

It is a cyclic number.

It is not a de Polignac number, because 645635242481 - 2¹⁴ = 645635226097 is a prime.

It is a super-2 number, since 2×645635242481² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (645635242487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322817621240 + 322817621241.

It is an arithmetic number, because the mean of its divisors is an integer number (322817621241).

Almost surely, 2^645635242481 is an apocalyptic number.

It is an amenable number.

645635242481 is a deficient number, since it is larger than the sum of its proper divisors (1).

645635242481 is an equidigital number, since it uses as much as digits as its factorization.

645635242481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5529600, while the sum is 50.

The spelling of 645635242481 in words is "six hundred forty-five billion, six hundred thirty-five million, two hundred forty-two thousand, four hundred eighty-one".