645876 has 72 divisors (see below), whose sum is σ = 2044224. Its totient is φ = 167040.

The previous prime is 645857. The next prime is 645877. The reversal of 645876 is 678546.

It is a happy number.

645876 is a `hidden beast` number, since 645 + 8 + 7 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 645876.

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 645876.

It is not an unprimeable number, because it can be changed into a prime (645877) 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, 2656 + ... + 2888.

It is an arithmetic number, because the mean of its divisors is an integer number (28392).

2⁶⁴⁵⁸⁷⁶ is an apocalyptic number.

645876 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645876, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1022112).

645876 is an abundant number, since it is smaller than the sum of its proper divisors (1398348).

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

645876 is a wasteful number, since it uses less digits than its factorization.

645876 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 256 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 645876 is about 803.6641089410. The cubic root of 645876 is about 86.4403232562.

It can be divided in two parts, 645 and 876, that added together give a square (1521 = 39²).

The spelling of 645876 in words is "six hundred forty-five thousand, eight hundred seventy-six".