645457040 has 20 divisors (see below), whose sum is σ = 1500687804. Its totient is φ = 258182784.

The previous prime is 645457009. The next prime is 645457049. The reversal of 645457040 is 40754546.

It can be written as a sum of positive squares in 2 ways, for example, as 378069136 + 267387904 = 19444^2 + 16352^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×645457040² = 833229580971123200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (645457049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4034027 + ... + 4034186.

Almost surely, 2^645457040 is an apocalyptic number.

It is an amenable number.

645457040 is an abundant number, since it is smaller than the sum of its proper divisors (855230764).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645457040 is a wasteful number, since it uses less digits than its factorization.

645457040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8068226 (or 8068220 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 35.

The square root of 645457040 is about 25405.8465712127. The cubic root of 645457040 is about 864.2162881581.

The spelling of 645457040 in words is "six hundred forty-five million, four hundred fifty-seven thousand, forty".