644077563 has 4 divisors (see below), whose sum is σ = 858770088. Its totient is φ = 429385040.

The previous prime is 644077543. The next prime is 644077573. The reversal of 644077563 is 365770446.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 644077563 - 2⁵ = 644077531 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644077543) 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, 107346258 + ... + 107346263.

It is an arithmetic number, because the mean of its divisors is an integer number (214692522).

Almost surely, 2^644077563 is an apocalyptic number.

644077563 is a deficient number, since it is larger than the sum of its proper divisors (214692525).

644077563 is a wasteful number, since it uses less digits than its factorization.

644077563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214692524.

The product of its (nonzero) digits is 423360, while the sum is 42.

The square root of 644077563 is about 25378.6832400737. The cubic root of 644077563 is about 863.6001785739.

The spelling of 644077563 in words is "six hundred forty-four million, seventy-seven thousand, five hundred sixty-three".