645431236651 has 2 divisors, whose sum is σ = 645431236652. Its totient is φ = 645431236650.

The previous prime is 645431236643. The next prime is 645431236657. The reversal of 645431236651 is 156632134546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645431236651 - 2³ = 645431236643 is a prime.

It is not a weakly prime, because it can be changed into another prime (645431236657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322715618325 + 322715618326.

It is an arithmetic number, because the mean of its divisors is an integer number (322715618326).

Almost surely, 2^645431236651 is an apocalyptic number.

645431236651 is a deficient number, since it is larger than the sum of its proper divisors (1).

645431236651 is an equidigital number, since it uses as much as digits as its factorization.

645431236651 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1555200, while the sum is 46.

The spelling of 645431236651 in words is "six hundred forty-five billion, four hundred thirty-one million, two hundred thirty-six thousand, six hundred fifty-one".