646622775 has 18 divisors (see below), whose sum is σ = 1158173640. Its totient is φ = 344865360.

The previous prime is 646622749. The next prime is 646622789. The reversal of 646622775 is 577226646.

It is not a de Polignac number, because 646622775 - 2¹⁰ = 646621751 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 646622775.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1436715 + ... + 1437164.

It is an arithmetic number, because the mean of its divisors is an integer number (64342980).

Almost surely, 2^646622775 is an apocalyptic number.

646622775 is a deficient number, since it is larger than the sum of its proper divisors (511550865).

646622775 is a wasteful number, since it uses less digits than its factorization.

646622775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2873895 (or 2873887 counting only the distinct ones).

The product of its digits is 846720, while the sum is 45.

The square root of 646622775 is about 25428.7784802967. The cubic root of 646622775 is about 864.7362511282.

It can be divided in two parts, 6466 and 22775, that added together give a square (29241 = 171²).

The spelling of 646622775 in words is "six hundred forty-six million, six hundred twenty-two thousand, seven hundred seventy-five".