645025517 has 2 divisors, whose sum is σ = 645025518. Its totient is φ = 645025516.

The previous prime is 645025487. The next prime is 645025531. The reversal of 645025517 is 715520546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 435181321 + 209844196 = 20861^2 + 14486^2 .

It is a cyclic number.

It is not a de Polignac number, because 645025517 - 2¹⁸ = 644763373 is a prime.

It is a super-2 number, since 2×645025517² = 832115835162234578, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645025597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322512758 + 322512759.

It is an arithmetic number, because the mean of its divisors is an integer number (322512759).

Almost surely, 2^645025517 is an apocalyptic number.

It is an amenable number.

645025517 is a deficient number, since it is larger than the sum of its proper divisors (1).

645025517 is an equidigital number, since it uses as much as digits as its factorization.

645025517 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 42000, while the sum is 35.

The square root of 645025517 is about 25397.3525588790. The cubic root of 645025517 is about 864.0236534198.

The spelling of 645025517 in words is "six hundred forty-five million, twenty-five thousand, five hundred seventeen".