644077634 has 4 divisors (see below), whose sum is σ = 966116454. Its totient is φ = 322038816.

The previous prime is 644077601. The next prime is 644077661. The reversal of 644077634 is 436770446.

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

It can be written as a sum of positive squares in only one way, i.e., 580954609 + 63123025 = 24103^2 + 7945^2 .

It is a junction number, because it is equal to n+sod(n) for n = 644077591 and 644077600.

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 as a sum of consecutive naturals, namely, 161019407 + ... + 161019410.

Almost surely, 2^644077634 is an apocalyptic number.

644077634 is a deficient number, since it is larger than the sum of its proper divisors (322038820).

644077634 is a wasteful number, since it uses less digits than its factorization.

644077634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322038819.

The product of its (nonzero) digits is 338688, while the sum is 41.

The square root of 644077634 is about 25378.6846388854. The cubic root of 644077634 is about 863.6002103069.

The spelling of 644077634 in words is "six hundred forty-four million, seventy-seven thousand, six hundred thirty-four".