645472 has 24 divisors (see below), whose sum is σ = 1327536. Its totient is φ = 308352.

The previous prime is 645467. The next prime is 645481. The reversal of 645472 is 274546.

It is a self number, because there is not a number n which added to its sum of digits gives 645472.

It is a congruent number.

It is an unprimeable number.

645472 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 3 ways as a sum of consecutive naturals, for example, 298 + ... + 1174.

It is an arithmetic number, because the mean of its divisors is an integer number (55314).

2⁶⁴⁵⁴⁷² 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 645472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (663768).

645472 is an abundant number, since it is smaller than the sum of its proper divisors (682064).

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

645472 is a wasteful number, since it uses less digits than its factorization.

645472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 910 (or 902 counting only the distinct ones).

The product of its digits is 6720, while the sum is 28.

The square root of 645472 is about 803.4127208353. The cubic root of 645472 is about 86.4222964862.

The spelling of 645472 in words is "six hundred forty-five thousand, four hundred seventy-two".