645001391 has 2 divisors, whose sum is σ = 645001392. Its totient is φ = 645001390.

The previous prime is 645001367. The next prime is 645001411. The reversal of 645001391 is 193100546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645001391 - 2¹⁴ = 644985007 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645001691) 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, 322500695 + 322500696.

It is an arithmetic number, because the mean of its divisors is an integer number (322500696).

Almost surely, 2^645001391 is an apocalyptic number.

645001391 is a deficient number, since it is larger than the sum of its proper divisors (1).

645001391 is an equidigital number, since it uses as much as digits as its factorization.

645001391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 645001391 is about 25396.8775836716. The cubic root of 645001391 is about 864.0128808772.

The spelling of 645001391 in words is "six hundred forty-five million, one thousand, three hundred ninety-one".