645942 has 16 divisors (see below), whose sum is σ = 1409472. Its totient is φ = 195720.

The previous prime is 645941. The next prime is 645973. The reversal of 645942 is 249546.

It is a d-powerful number, because it can be written as 6⁶ + 4⁴ + 9⁶ + 5 + 4⁸ + 2¹¹ .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4828 + ... + 4959.

It is an arithmetic number, because the mean of its divisors is an integer number (88092).

2⁶⁴⁵⁹⁴² is an apocalyptic number.

645942 is an abundant number, since it is smaller than the sum of its proper divisors (763530).

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

645942 is a wasteful number, since it uses less digits than its factorization.

645942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9803.

The product of its digits is 8640, while the sum is 30.

The square root of 645942 is about 803.7051698229. The cubic root of 645942 is about 86.4432675092.

It can be divided in two parts, 64 and 5942, that added together give a palindrome (6006).

The spelling of 645942 in words is "six hundred forty-five thousand, nine hundred forty-two".