645287 has 4 divisors (see below), whose sum is σ = 650496. Its totient is φ = 640080.

The previous prime is 645257. The next prime is 645313. The reversal of 645287 is 782546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 782546 = 2 ⋅391273.

It is not a de Polignac number, because 645287 - 2¹⁸ = 383143 is a prime.

It is a Duffinian number.

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 645287.

It is not an unprimeable number, because it can be changed into a prime (645257) 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 in 3 ways as a sum of consecutive naturals, for example, 2414 + ... + 2667.

It is an arithmetic number, because the mean of its divisors is an integer number (162624).

2⁶⁴⁵²⁸⁷ is an apocalyptic number.

645287 is a deficient number, since it is larger than the sum of its proper divisors (5209).

645287 is a wasteful number, since it uses less digits than its factorization.

645287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5208.

The product of its digits is 13440, while the sum is 32.

The square root of 645287 is about 803.2975787341. The cubic root of 645287 is about 86.4140391424.

The spelling of 645287 in words is "six hundred forty-five thousand, two hundred eighty-seven".