645253626352537 has 2 divisors, whose sum is σ = 645253626352538. Its totient is φ = 645253626352536.

The previous prime is 645253626352483. The next prime is 645253626352541. The reversal of 645253626352537 is 735253626352546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 459939966256521 + 185313660096016 = 21446211^2 + 13612996^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645253626352537 is a prime.

It is a super-3 number, since 3×645253626352537³ (a number of 45 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (645253626352637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322626813176268 + 322626813176269.

It is an arithmetic number, because the mean of its divisors is an integer number (322626813176269).

Almost surely, 2^{645253626352537} is an apocalyptic number.

It is an amenable number.

645253626352537 is a deficient number, since it is larger than the sum of its proper divisors (1).

645253626352537 is an equidigital number, since it uses as much as digits as its factorization.

645253626352537 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 816480000, while the sum is 64.

Subtracting 645253626352537 from its reverse (735253626352546), we obtain a palindrome (90000000000009).

The spelling of 645253626352537 in words is "six hundred forty-five trillion, two hundred fifty-three billion, six hundred twenty-six million, three hundred fifty-two thousand, five hundred thirty-seven".