645802 has 4 divisors (see below), whose sum is σ = 968706. Its totient is φ = 322900.

The previous prime is 645787. The next prime is 645803. The reversal of 645802 is 208546.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 549081 + 96721 = 741^2 + 311^2 .

It is not an unprimeable number, because it can be changed into a prime (645803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161449 + ... + 161452.

2⁶⁴⁵⁸⁰² is an apocalyptic number.

645802 is a deficient number, since it is larger than the sum of its proper divisors (322904).

645802 is a wasteful number, since it uses less digits than its factorization.

645802 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322903.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 645802 is about 803.6180684878. The cubic root of 645802 is about 86.4370218856.

The spelling of 645802 in words is "six hundred forty-five thousand, eight hundred two".