645031 has 8 divisors (see below), whose sum is σ = 719280. Its totient is φ = 574848.

The previous prime is 645023. The next prime is 645037. The reversal of 645031 is 130546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645031 - 2³ = 645023 is a prime.

It is a super-2 number, since 2×645031² = 832129981922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 676 + ... + 1321.

It is an arithmetic number, because the mean of its divisors is an integer number (89910).

2⁶⁴⁵⁰³¹ is an apocalyptic number.

645031 is a deficient number, since it is larger than the sum of its proper divisors (74249).

645031 is a wasteful number, since it uses less digits than its factorization.

645031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2033.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 645031 is about 803.1382197356. The cubic root of 645031 is about 86.4026101606.

Adding to 645031 its reverse (130546), we get a palindrome (775577).

The spelling of 645031 in words is "six hundred forty-five thousand, thirty-one".