645072 has 40 divisors (see below), whose sum is σ = 1696320. Its totient is φ = 211200.

The previous prime is 645067. The next prime is 645077. The reversal of 645072 is 270546.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (645067) and next prime (645077).

It is a super-2 number, since 2×645072² = 832235770368, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a d-powerful number, because it can be written as 6 + 4 + 0 + 5⁵ + 7⁶ + 2¹⁹ .

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 645072.

It is not an unprimeable number, because it can be changed into a prime (645077) by changing a digit.

645072 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4197 + ... + 4347.

It is an arithmetic number, because the mean of its divisors is an integer number (42408).

2⁶⁴⁵⁰⁷² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (848160).

645072 is an abundant number, since it is smaller than the sum of its proper divisors (1051248).

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

645072 is a wasteful number, since it uses less digits than its factorization.

645072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 645072 is about 803.1637442016. The cubic root of 645072 is about 86.4044407868.

The spelling of 645072 in words is "six hundred forty-five thousand, seventy-two".