645734651 has 2 divisors, whose sum is σ = 645734652. Its totient is φ = 645734650.

The previous prime is 645734629. The next prime is 645734653. The reversal of 645734651 is 156437546.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645734651 is a prime.

It is a Sophie Germain prime.

Together with 645734653, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 645734599 and 645734608.

It is not a weakly prime, because it can be changed into another prime (645734653) 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, 322867325 + 322867326.

It is an arithmetic number, because the mean of its divisors is an integer number (322867326).

Almost surely, 2^645734651 is an apocalyptic number.

645734651 is a deficient number, since it is larger than the sum of its proper divisors (1).

645734651 is an equidigital number, since it uses as much as digits as its factorization.

645734651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 302400, while the sum is 41.

The square root of 645734651 is about 25411.3095097439. The cubic root of 645734651 is about 864.3401701752.

The spelling of 645734651 in words is "six hundred forty-five million, seven hundred thirty-four thousand, six hundred fifty-one".