644274 has 40 divisors (see below), whose sum is σ = 1494108. Its totient is φ = 207360.

The previous prime is 644261. The next prime is 644291. The reversal of 644274 is 472446.

644274 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 585225 + 59049 = 765^2 + 243^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6594 + ... + 6690.

2⁶⁴⁴²⁷⁴ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644274, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (747054).

644274 is an abundant number, since it is smaller than the sum of its proper divisors (849834).

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

644274 is a wasteful number, since it uses less digits than its factorization.

644274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152 (or 143 counting only the distinct ones).

The product of its digits is 5376, while the sum is 27.

The square root of 644274 is about 802.6668050941. Note that the first 3 decimals coincide. The cubic root of 644274 is about 86.3687966026.

The spelling of 644274 in words is "six hundred forty-four thousand, two hundred seventy-four".