645092996539761 has 243 divisors, whose sum is σ = 1220258376249003. Its totient is φ = 327191904325440.

The previous prime is 645092996539751. The next prime is 645092996539769. The reversal of 645092996539761 is 167935699290546.

The square root of 645092996539761 is 25398681.

It is a perfect power (a square), and thus also a powerful number.

645092996539761 is a `hidden beast` number, since 6 + 4 + 5 + 0 + 9 + 2 + 9 + 9 + 6 + 539 + 76 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 276815556950625 + 368277439589136 = 16637775^2 + 19190556^2 .

It is not a de Polignac number, because 645092996539761 - 2¹⁹ = 645092996015473 is a prime.

It is a super-2 number, since 2×645092996539761² (a number of 30 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (645092996539769) by changing a digit.

It is a polite number, since it can be written in 242 ways as a sum of consecutive naturals, for example, 252285097095 + ... + 252285099651.

Almost surely, 2^{645092996539761} is an apocalyptic number.

645092996539761 is the 25398681-st square number.

645092996539761 is the 12699341-st centered octagonal number.

It is an amenable number.

645092996539761 is a deficient number, since it is larger than the sum of its proper divisors (575165379709242).

645092996539761 is an equidigital number, since it uses as much as digits as its factorization.

645092996539761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5242 (or 2621 counting only the distinct ones).

The product of its (nonzero) digits is 5952139200, while the sum is 81.

The spelling of 645092996539761 in words is "six hundred forty-five trillion, ninety-two billion, nine hundred ninety-six million, five hundred thirty-nine thousand, seven hundred sixty-one".