644324997 has 8 divisors (see below), whose sum is σ = 871922656. Its totient is φ = 423138672.

The previous prime is 644324971. The next prime is 644325001. The reversal of 644324997 is 799423446.

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

It is not a de Polignac number, because 644324997 - 2⁸ = 644324741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644324917) 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, 1602598 + ... + 1602999.

It is an arithmetic number, because the mean of its divisors is an integer number (108990332).

Almost surely, 2^644324997 is an apocalyptic number.

644324997 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

It is an amenable number.

644324997 is a deficient number, since it is larger than the sum of its proper divisors (227597659).

644324997 is a wasteful number, since it uses less digits than its factorization.

644324997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3205667.

The product of its digits is 1306368, while the sum is 48.

The square root of 644324997 is about 25383.5576111781. The cubic root of 644324997 is about 863.7107536046.

The spelling of 644324997 in words is "six hundred forty-four million, three hundred twenty-four thousand, nine hundred ninety-seven".