646721774 has 16 divisors (see below), whose sum is σ = 1029421440. Its totient is φ = 304058040.

The previous prime is 646721773. The next prime is 646721821. The reversal of 646721774 is 477127646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646721773) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116432 + ... + 121859.

It is an arithmetic number, because the mean of its divisors is an integer number (64338840).

Almost surely, 2^646721774 is an apocalyptic number.

646721774 is a deficient number, since it is larger than the sum of its proper divisors (382699666).

646721774 is a wasteful number, since it uses less digits than its factorization.

646721774 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238375.

The product of its digits is 395136, while the sum is 44.

The square root of 646721774 is about 25430.7249994962. The cubic root of 646721774 is about 864.7803797190.

The spelling of 646721774 in words is "six hundred forty-six million, seven hundred twenty-one thousand, seven hundred seventy-four".