645396 has 12 divisors (see below), whose sum is σ = 1505952. Its totient is φ = 215128.

The previous prime is 645383. The next prime is 645397. The reversal of 645396 is 693546.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

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 645396.

It is not an unprimeable number, because it can be changed into a prime (645397) by changing a digit.

645396 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, 26880 + ... + 26903.

It is an arithmetic number, because the mean of its divisors is an integer number (125496).

2⁶⁴⁵³⁹⁶ is an apocalyptic number.

It is an amenable number.

645396 is an abundant number, since it is smaller than the sum of its proper divisors (860556).

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

645396 is a wasteful number, since it uses less digits than its factorization.

645396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53790 (or 53788 counting only the distinct ones).

The product of its digits is 19440, while the sum is 33.

The square root of 645396 is about 803.3654212125. The cubic root of 645396 is about 86.4189044710.

It can be divided in two parts, 64 and 5396, that added together give a triangular number (5460 = T₁₀₄).

The spelling of 645396 in words is "six hundred forty-five thousand, three hundred ninety-six".