645946451 has 2 divisors, whose sum is σ = 645946452. Its totient is φ = 645946450.

The previous prime is 645946447. The next prime is 645946463. The reversal of 645946451 is 154649546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645946451 - 2² = 645946447 is a prime.

It is a Chen prime.

It is equal to p_33593588 and since 645946451 and 33593588 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (645946151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322973225 + 322973226.

It is an arithmetic number, because the mean of its divisors is an integer number (322973226).

Almost surely, 2^645946451 is an apocalyptic number.

645946451 is a deficient number, since it is larger than the sum of its proper divisors (1).

645946451 is an equidigital number, since it uses as much as digits as its factorization.

645946451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 518400, while the sum is 44.

The square root of 645946451 is about 25415.4766038333. The cubic root of 645946451 is about 864.4346606062.

The spelling of 645946451 in words is "six hundred forty-five million, nine hundred forty-six thousand, four hundred fifty-one".