644979107 has 8 divisors (see below), whose sum is σ = 647483760. Its totient is φ = 642480160.

The previous prime is 644979037. The next prime is 644979121. The reversal of 644979107 is 701979446.

It is a happy number.

644979107 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 644979107 - 2¹⁰ = 644978083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644979197) 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, 469073 + ... + 470445.

It is an arithmetic number, because the mean of its divisors is an integer number (80935470).

Almost surely, 2^644979107 is an apocalyptic number.

644979107 is a deficient number, since it is larger than the sum of its proper divisors (2504653).

644979107 is a wasteful number, since it uses less digits than its factorization.

644979107 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2853.

The product of its (nonzero) digits is 381024, while the sum is 47.

The square root of 644979107 is about 25396.4388645337. The cubic root of 644979107 is about 864.0029305706.

The spelling of 644979107 in words is "six hundred forty-four million, nine hundred seventy-nine thousand, one hundred seven".