644070 has 32 divisors (see below), whose sum is σ = 1767168. Its totient is φ = 147168.

The previous prime is 644057. The next prime is 644089. The reversal of 644070 is 70446.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644070.

It is an unprimeable number.

644070 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1324 + ... + 1743.

It is an arithmetic number, because the mean of its divisors is an integer number (55224).

2⁶⁴⁴⁰⁷⁰ is an apocalyptic number.

644070 is an abundant number, since it is smaller than the sum of its proper divisors (1123098).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644070 is a wasteful number, since it uses less digits than its factorization.

644070 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3084.

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 644070 is about 802.5397186433. The cubic root of 644070 is about 86.3596798322.

The spelling of 644070 in words is "six hundred forty-four thousand, seventy".