644948403 has 8 divisors (see below), whose sum is σ = 938106816. Its totient is φ = 390877800.

The previous prime is 644948399. The next prime is 644948471. The reversal of 644948403 is 304849446.

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

It is not a de Polignac number, because 644948403 - 2² = 644948399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644948203) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9771913 + ... + 9771978.

It is an arithmetic number, because the mean of its divisors is an integer number (117263352).

Almost surely, 2^644948403 is an apocalyptic number.

644948403 is a deficient number, since it is larger than the sum of its proper divisors (293158413).

644948403 is a wasteful number, since it uses less digits than its factorization.

644948403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19543905.

The product of its (nonzero) digits is 331776, while the sum is 42.

The square root of 644948403 is about 25395.8343631392. The cubic root of 644948403 is about 863.9892201694.

The spelling of 644948403 in words is "six hundred forty-four million, nine hundred forty-eight thousand, four hundred three".