645644457 has 6 divisors (see below), whose sum is σ = 932597562. Its totient is φ = 430429632.

The previous prime is 645644449. The next prime is 645644473. The reversal of 645644457 is 754446546.

645644457 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 563397696 + 82246761 = 23736^2 + 9069^2 .

It is not a de Polignac number, because 645644457 - 2³ = 645644449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645644437) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35869128 + ... + 35869145.

It is an arithmetic number, because the mean of its divisors is an integer number (155432927).

Almost surely, 2^645644457 is an apocalyptic number.

It is an amenable number.

645644457 is a deficient number, since it is larger than the sum of its proper divisors (286953105).

645644457 is a wasteful number, since it uses less digits than its factorization.

645644457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71738279 (or 71738276 counting only the distinct ones).

The product of its digits is 1612800, while the sum is 45.

The square root of 645644457 is about 25409.5347655167. The cubic root of 645644457 is about 864.2999256119.

The spelling of 645644457 in words is "six hundred forty-five million, six hundred forty-four thousand, four hundred fifty-seven".