645291863 has 2 divisors, whose sum is σ = 645291864. Its totient is φ = 645291862.

The previous prime is 645291839. The next prime is 645291901. The reversal of 645291863 is 368192546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645291863 - 2⁶ = 645291799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645291463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322645931 + 322645932.

It is an arithmetic number, because the mean of its divisors is an integer number (322645932).

Almost surely, 2^645291863 is an apocalyptic number.

645291863 is a deficient number, since it is larger than the sum of its proper divisors (1).

645291863 is an equidigital number, since it uses as much as digits as its factorization.

645291863 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 44.

The square root of 645291863 is about 25402.5955957260. The cubic root of 645291863 is about 864.1425621916.

The spelling of 645291863 in words is "six hundred forty-five million, two hundred ninety-one thousand, eight hundred sixty-three".