644424155 has 8 divisors (see below), whose sum is σ = 778873200. Its totient is φ = 511829856.

The previous prime is 644424149. The next prime is 644424161. The reversal of 644424155 is 551424446.

644424155 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (644424149) and next prime (644424161).

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644424155 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 462920 + ... + 464309.

It is an arithmetic number, because the mean of its divisors is an integer number (97359150).

Almost surely, 2^644424155 is an apocalyptic number.

644424155 is a deficient number, since it is larger than the sum of its proper divisors (134449045).

644424155 is a wasteful number, since it uses less digits than its factorization.

644424155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 927373.

The product of its digits is 76800, while the sum is 35.

The square root of 644424155 is about 25385.5107295481. The cubic root of 644424155 is about 863.7550580774.

The spelling of 644424155 in words is "six hundred forty-four million, four hundred twenty-four thousand, one hundred fifty-five".