646720263 has 24 divisors (see below), whose sum is σ = 1069005600. Its totient is φ = 369068544.

The previous prime is 646720253. The next prime is 646720289. The reversal of 646720263 is 362027646.

It is a happy number.

646720263 is a `hidden beast` number, since 646 + 7 + 2 + 0 + 2 + 6 + 3 = 666.

It is not a de Polignac number, because 646720263 - 2⁶ = 646720199 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646720223) by changing a digit.

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 in 23 ways as a sum of consecutive naturals, for example, 44623 + ... + 57311.

It is an arithmetic number, because the mean of its divisors is an integer number (44541900).

Almost surely, 2^646720263 is an apocalyptic number.

646720263 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

646720263 is a deficient number, since it is larger than the sum of its proper divisors (422285337).

646720263 is a wasteful number, since it uses less digits than its factorization.

646720263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13511 (or 13508 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 36.

The square root of 646720263 is about 25430.6952913207. The cubic root of 646720263 is about 864.7797062279.

The spelling of 646720263 in words is "six hundred forty-six million, seven hundred twenty thousand, two hundred sixty-three".