645097844 has 12 divisors (see below), whose sum is σ = 1195328484. Its totient is φ = 303575424.

The previous prime is 645097811. The next prime is 645097877. The reversal of 645097844 is 448790546.

It is an interprime number because it is at equal distance from previous prime (645097811) and next prime (645097877).

It can be written as a sum of positive squares in 2 ways, for example, as 567868900 + 77228944 = 23830^2 + 8788^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4743299 + ... + 4743434.

It is an arithmetic number, because the mean of its divisors is an integer number (99610707).

Almost surely, 2^645097844 is an apocalyptic number.

It is an amenable number.

645097844 is a deficient number, since it is larger than the sum of its proper divisors (550230640).

645097844 is a wasteful number, since it uses less digits than its factorization.

645097844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9486754 (or 9486752 counting only the distinct ones).

The product of its (nonzero) digits is 967680, while the sum is 47.

The square root of 645097844 is about 25398.7764272218. The cubic root of 645097844 is about 864.0559466658.

The spelling of 645097844 in words is "six hundred forty-five million, ninety-seven thousand, eight hundred forty-four".