645655 has 8 divisors (see below), whose sum is σ = 781200. Its totient is φ = 512256.

The previous prime is 645649. The next prime is 645661. The reversal of 645655 is 556546.

It is an interprime number because it is at equal distance from previous prime (645649) and next prime (645661).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645655 - 2³ = 645647 is a prime.

It is a super-3 number, since 3×645655³ = 807463333708159125, which contains 333 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645655.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 231 + ... + 1159.

It is an arithmetic number, because the mean of its divisors is an integer number (97650).

2⁶⁴⁵⁶⁵⁵ is an apocalyptic number.

645655 is a deficient number, since it is larger than the sum of its proper divisors (135545).

645655 is a wasteful number, since it uses less digits than its factorization.

645655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073.

The product of its digits is 18000, while the sum is 31.

The square root of 645655 is about 803.5266019243. The cubic root of 645655 is about 86.4304630092.

The spelling of 645655 in words is "six hundred forty-five thousand, six hundred fifty-five".