645655677 has 4 divisors (see below), whose sum is σ = 860874240. Its totient is φ = 430437116.

The previous prime is 645655651. The next prime is 645655687. The reversal of 645655677 is 776556546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645655677 - 2⁸ = 645655421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645655687) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107609277 + ... + 107609282.

It is an arithmetic number, because the mean of its divisors is an integer number (215218560).

Almost surely, 2^645655677 is an apocalyptic number.

It is an amenable number.

645655677 is a deficient number, since it is larger than the sum of its proper divisors (215218563).

645655677 is a wasteful number, since it uses less digits than its factorization.

645655677 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215218562.

The product of its digits is 5292000, while the sum is 51.

The square root of 645655677 is about 25409.7555478206. The cubic root of 645655677 is about 864.3049321801.

The spelling of 645655677 in words is "six hundred forty-five million, six hundred fifty-five thousand, six hundred seventy-seven".