645172 has 36 divisors (see below), whose sum is σ = 1310848. Its totient is φ = 277200.

The previous prime is 645149. The next prime is 645179. The reversal of 645172 is 271546.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645179) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14983 + ... + 15025.

2⁶⁴⁵¹⁷² is an apocalyptic number.

645172 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

645172 is an abundant number, since it is smaller than the sum of its proper divisors (665676).

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

645172 is a wasteful number, since it uses less digits than its factorization.

645172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100 (or 87 counting only the distinct ones).

The product of its digits is 1680, while the sum is 25.

The square root of 645172 is about 803.2259955953. The cubic root of 645172 is about 86.4089054035.

The spelling of 645172 in words is "six hundred forty-five thousand, one hundred seventy-two".