644596646 has 8 divisors (see below), whose sum is σ = 980513424. Its totient is φ = 317758840.

The previous prime is 644596637. The next prime is 644596649. The reversal of 644596646 is 646695446.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644596594 and 644596603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644596649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2269565 + ... + 2269848.

It is an arithmetic number, because the mean of its divisors is an integer number (122564178).

Almost surely, 2^644596646 is an apocalyptic number.

644596646 is a deficient number, since it is larger than the sum of its proper divisors (335916778).

644596646 is a wasteful number, since it uses less digits than its factorization.

644596646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4539486.

The product of its digits is 3732480, while the sum is 50.

The square root of 644596646 is about 25388.9079324023. The cubic root of 644596646 is about 863.8321174082.

The spelling of 644596646 in words is "six hundred forty-four million, five hundred ninety-six thousand, six hundred forty-six".