646649723 has 8 divisors (see below), whose sum is σ = 685901520. Its totient is φ = 607532800.

The previous prime is 646649699. The next prime is 646649737. The reversal of 646649723 is 327946646.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 646649723 - 2⁸ = 646649467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646649023) 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 7 ways as a sum of consecutive naturals, for example, 23753 + ... + 43098.

It is an arithmetic number, because the mean of its divisors is an integer number (85737690).

Almost surely, 2^646649723 is an apocalyptic number.

646649723 is a deficient number, since it is larger than the sum of its proper divisors (39251797).

646649723 is a wasteful number, since it uses less digits than its factorization.

646649723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67437.

The product of its digits is 1306368, while the sum is 47.

The square root of 646649723 is about 25429.3083468662. The cubic root of 646649723 is about 864.7482635872.

The spelling of 646649723 in words is "six hundred forty-six million, six hundred forty-nine thousand, seven hundred twenty-three".