644409977 has 8 divisors (see below), whose sum is σ = 660055200. Its totient is φ = 628922304.

The previous prime is 644409971. The next prime is 644409979. The reversal of 644409977 is 779904446.

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 644409977 - 2¹⁴ = 644393593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644409971) 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, 31088 + ... + 47489.

It is an arithmetic number, because the mean of its divisors is an integer number (82506900).

Almost surely, 2^644409977 is an apocalyptic number.

It is an amenable number.

644409977 is a deficient number, since it is larger than the sum of its proper divisors (15645223).

644409977 is a wasteful number, since it uses less digits than its factorization.

644409977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78775.

The product of its (nonzero) digits is 1524096, while the sum is 50.

The square root of 644409977 is about 25385.2314742253. The cubic root of 644409977 is about 863.7487235285.

The spelling of 644409977 in words is "six hundred forty-four million, four hundred nine thousand, nine hundred seventy-seven".