646641366 has 32 divisors (see below), whose sum is σ = 1542302208. Its totient is φ = 176721600.

The previous prime is 646641311. The next prime is 646641367. The reversal of 646641366 is 663146646.

It is a super-5 number, since 5×646641366⁵ (a number of 45 digits) contains 55555 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646641367) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 333735 + ... + 335666.

It is an arithmetic number, because the mean of its divisors is an integer number (48196944).

Almost surely, 2^646641366 is an apocalyptic number.

646641366 is an abundant number, since it is smaller than the sum of its proper divisors (895660842).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646641366 is a wasteful number, since it uses less digits than its factorization.

646641366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669436.

The product of its digits is 373248, while the sum is 42.

The square root of 646641366 is about 25429.1440280635. The cubic root of 646641366 is about 864.7445383698.

The spelling of 646641366 in words is "six hundred forty-six million, six hundred forty-one thousand, three hundred sixty-six".