645498 has 48 divisors (see below), whose sum is σ = 1647360. Its totient is φ = 178848.

The previous prime is 645497. The next prime is 645499. The reversal of 645498 is 894546.

645498 is a `hidden beast` number, since 645 + 4 + 9 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (645497) and next prime (645499).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (645493) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5868 + ... + 5976.

It is an arithmetic number, because the mean of its divisors is an integer number (34320).

2⁶⁴⁵⁴⁹⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645498, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (823680).

645498 is an abundant number, since it is smaller than the sum of its proper divisors (1001862).

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

645498 is a wasteful number, since it uses less digits than its factorization.

645498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171 (or 168 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 645498 is about 803.4289016459. The cubic root of 645498 is about 86.4234568513.

The spelling of 645498 in words is "six hundred forty-five thousand, four hundred ninety-eight".