645633 has 12 divisors (see below), whose sum is σ = 973440. Its totient is φ = 411576.

The previous prime is 645629. The next prime is 645641. The reversal of 645633 is 336546.

It is not a de Polignac number, because 645633 - 2² = 645629 is a prime.

645633 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 645597 and 645606.

It is not an unprimeable number, because it can be changed into a prime (645683) 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, 1353 + ... + 1766.

It is an arithmetic number, because the mean of its divisors is an integer number (81120).

2⁶⁴⁵⁶³³ is an apocalyptic number.

It is an amenable number.

645633 is a deficient number, since it is larger than the sum of its proper divisors (327807).

645633 is a wasteful number, since it uses less digits than its factorization.

645633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3148 (or 3145 counting only the distinct ones).

The product of its digits is 6480, while the sum is 27.

The square root of 645633 is about 803.5129121551. The cubic root of 645633 is about 86.4294813230.

The spelling of 645633 in words is "six hundred forty-five thousand, six hundred thirty-three".