646766558 has 4 divisors (see below), whose sum is σ = 970149840. Its totient is φ = 323383278.

The previous prime is 646766551. The next prime is 646766567. The reversal of 646766558 is 855667646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 855667646 = 2 ⋅427833823.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646766551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161691638 + ... + 161691641.

It is an arithmetic number, because the mean of its divisors is an integer number (242537460).

Almost surely, 2^646766558 is an apocalyptic number.

646766558 is a deficient number, since it is larger than the sum of its proper divisors (323383282).

646766558 is a wasteful number, since it uses less digits than its factorization.

646766558 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323383281.

The product of its digits is 7257600, while the sum is 53.

The square root of 646766558 is about 25431.6054939518. The cubic root of 646766558 is about 864.8003406111.

The spelling of 646766558 in words is "six hundred forty-six million, seven hundred sixty-six thousand, five hundred fifty-eight".