645713969 has 2 divisors, whose sum is σ = 645713970. Its totient is φ = 645713968.

The previous prime is 645713963. The next prime is 645713977. The reversal of 645713969 is 969317546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 561073969 + 84640000 = 23687^2 + 9200^2 .

It is a cyclic number.

It is not a de Polignac number, because 645713969 - 2⁴ = 645713953 is a prime.

It is a super-2 number, since 2×645713969² = 833893059523465922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (645713963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322856984 + 322856985.

It is an arithmetic number, because the mean of its divisors is an integer number (322856985).

Almost surely, 2^645713969 is an apocalyptic number.

It is an amenable number.

645713969 is a deficient number, since it is larger than the sum of its proper divisors (1).

645713969 is an equidigital number, since it uses as much as digits as its factorization.

645713969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1224720, while the sum is 50.

The square root of 645713969 is about 25410.9025616958. The cubic root of 645713969 is about 864.3309421979.

The spelling of 645713969 in words is "six hundred forty-five million, seven hundred thirteen thousand, nine hundred sixty-nine".