644370 has 32 divisors (see below), whose sum is σ = 1582848. Its totient is φ = 167808.

The previous prime is 644363. The next prime is 644377. The reversal of 644370 is 73446.

It is an interprime number because it is at equal distance from previous prime (644363) and next prime (644377).

It is a self number, because there is not a number n which added to its sum of digits gives 644370.

It is not an unprimeable number, because it can be changed into a prime (644377) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1182 + ... + 1638.

It is an arithmetic number, because the mean of its divisors is an integer number (49464).

2⁶⁴⁴³⁷⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644370, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (791424).

644370 is an abundant number, since it is smaller than the sum of its proper divisors (938478).

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

644370 is a wasteful number, since it uses less digits than its factorization.

644370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514.

The product of its (nonzero) digits is 2016, while the sum is 24.

The square root of 644370 is about 802.7266035208. The cubic root of 644370 is about 86.3730861816.

The spelling of 644370 in words is "six hundred forty-four thousand, three hundred seventy".