646727818 has 24 divisors (see below), whose sum is σ = 1082241216. Its totient is φ = 289572360.

The previous prime is 646727813. The next prime is 646727819. The reversal of 646727818 is 818727646.

It is a happy number.

It is a super-2 number, since 2×646727818² = 836513741150082248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (646727813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3730 + ... + 36157.

It is an arithmetic number, because the mean of its divisors is an integer number (45093384).

Almost surely, 2^646727818 is an apocalyptic number.

646727818 is a deficient number, since it is larger than the sum of its proper divisors (435513398).

646727818 is a wasteful number, since it uses less digits than its factorization.

646727818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39978 (or 39967 counting only the distinct ones).

The product of its digits is 903168, while the sum is 49.

The square root of 646727818 is about 25430.8438318511. The cubic root of 646727818 is about 864.7830736731.

The spelling of 646727818 in words is "six hundred forty-six million, seven hundred twenty-seven thousand, eight hundred eighteen".