645255405 has 12 divisors (see below), whose sum is σ = 1118442780. Its totient is φ = 344136192.

The previous prime is 645255343. The next prime is 645255419. The reversal of 645255405 is 504552546.

645255405 is a `hidden beast` number, since 64 + 52 + 5 + 540 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 76003524 + 569251881 = 8718^2 + 23859^2 .

It is not a de Polignac number, because 645255405 - 2⁷ = 645255277 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645255405.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7169460 + ... + 7169549.

It is an arithmetic number, because the mean of its divisors is an integer number (93203565).

Almost surely, 2^645255405 is an apocalyptic number.

It is an amenable number.

645255405 is a deficient number, since it is larger than the sum of its proper divisors (473187375).

645255405 is a wasteful number, since it uses less digits than its factorization.

645255405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14339020 (or 14339017 counting only the distinct ones).

The product of its (nonzero) digits is 120000, while the sum is 36.

The square root of 645255405 is about 25401.8779817556. The cubic root of 645255405 is about 864.1262876422.

The spelling of 645255405 in words is "six hundred forty-five million, two hundred fifty-five thousand, four hundred five".