644614994 has 8 divisors (see below), whose sum is σ = 976310400. Its totient is φ = 319178196.

The previous prime is 644614981. The next prime is 644615009. The reversal of 644614994 is 499416446.

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

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1564394 + ... + 1564805.

It is an arithmetic number, because the mean of its divisors is an integer number (122038800).

Almost surely, 2^644614994 is an apocalyptic number.

644614994 is a deficient number, since it is larger than the sum of its proper divisors (331695406).

644614994 is a wasteful number, since it uses less digits than its factorization.

644614994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3129304.

The product of its digits is 746496, while the sum is 47.

The square root of 644614994 is about 25389.2692687285. The cubic root of 644614994 is about 863.8403134594.

The spelling of 644614994 in words is "six hundred forty-four million, six hundred fourteen thousand, nine hundred ninety-four".