646723768 has 8 divisors (see below), whose sum is σ = 1212607080. Its totient is φ = 323361880.

The previous prime is 646723757. The next prime is 646723787. The reversal of 646723768 is 867327646.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×646723768² = 836503264192235648, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40420228 + ... + 40420243.

It is an arithmetic number, because the mean of its divisors is an integer number (151575885).

Almost surely, 2^646723768 is an apocalyptic number.

It is an amenable number.

646723768 is a deficient number, since it is larger than the sum of its proper divisors (565883312).

646723768 is a wasteful number, since it uses less digits than its factorization.

646723768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80840477 (or 80840473 counting only the distinct ones).

The product of its digits is 2032128, while the sum is 49.

The square root of 646723768 is about 25430.7642040109. The cubic root of 646723768 is about 864.7812684939.

The spelling of 646723768 in words is "six hundred forty-six million, seven hundred twenty-three thousand, seven hundred sixty-eight".