640555045 has 16 divisors (see below), whose sum is σ = 856341360. Its totient is φ = 456712704.

The previous prime is 640555031. The next prime is 640555061. The reversal of 640555045 is 540555046.

It can be written as a sum of positive squares in 8 ways, for example, as 26357956 + 614197089 = 5134^2 + 24783^2 .

It is a cyclic number.

It is not a de Polignac number, because 640555045 - 2¹³ = 640546853 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640555045.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 168024 + ... + 171793.

It is an arithmetic number, because the mean of its divisors is an integer number (53521335).

Almost surely, 2^640555045 is an apocalyptic number.

640555045 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

640555045 is a deficient number, since it is larger than the sum of its proper divisors (215786315).

640555045 is a wasteful number, since it uses less digits than its factorization.

640555045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339864.

The product of its (nonzero) digits is 60000, while the sum is 34.

The square root of 640555045 is about 25309.1889439389. The cubic root of 640555045 is about 862.0229307373.

Subtracting from 640555045 its reverse (540555046), we obtain a palindrome (99999999).

The spelling of 640555045 in words is "six hundred forty million, five hundred fifty-five thousand, forty-five".