645791995 has 4 divisors (see below), whose sum is σ = 774950400. Its totient is φ = 516633592.

The previous prime is 645791989. The next prime is 645792011. The reversal of 645791995 is 599197546.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645791995 - 2³ = 645791987 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64579195 + ... + 64579204.

It is an arithmetic number, because the mean of its divisors is an integer number (193737600).

Almost surely, 2^645791995 is an apocalyptic number.

645791995 is a deficient number, since it is larger than the sum of its proper divisors (129158405).

645791995 is a wasteful number, since it uses less digits than its factorization.

645791995 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129158404.

The product of its digits is 3061800, while the sum is 55.

The square root of 645791995 is about 25412.4378012028. The cubic root of 645791995 is about 864.3657551197.

The spelling of 645791995 in words is "six hundred forty-five million, seven hundred ninety-one thousand, nine hundred ninety-five".