645388 has 12 divisors (see below), whose sum is σ = 1195992. Its totient is φ = 303680.

The previous prime is 645383. The next prime is 645397. The reversal of 645388 is 883546.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (645383) by changing a digit.

645388 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, 4678 + ... + 4813.

It is an arithmetic number, because the mean of its divisors is an integer number (99666).

2⁶⁴⁵³⁸⁸ is an apocalyptic number.

645388 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

645388 is a deficient number, since it is larger than the sum of its proper divisors (550604).

645388 is a wasteful number, since it uses less digits than its factorization.

645388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9512 (or 9510 counting only the distinct ones).

The product of its digits is 23040, while the sum is 34.

The square root of 645388 is about 803.3604421429. The cubic root of 645388 is about 86.4185474013.

It can be divided in two parts, 64538 and 8, that added together give a palindrome (64546).

The spelling of 645388 in words is "six hundred forty-five thousand, three hundred eighty-eight".