645841 has 8 divisors (see below), whose sum is σ = 743040. Its totient is φ = 549888.

The previous prime is 645839. The next prime is 645851. The reversal of 645841 is 148546.

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 645841 - 2¹ = 645839 is a prime.

It is a super-2 number, since 2×645841² = 834221194562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645851) 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 7 ways as a sum of consecutive naturals, for example, 1620 + ... + 1978.

It is an arithmetic number, because the mean of its divisors is an integer number (92880).

2⁶⁴⁵⁸⁴¹ is an apocalyptic number.

It is an amenable number.

645841 is a deficient number, since it is larger than the sum of its proper divisors (97199).

645841 is a wasteful number, since it uses less digits than its factorization.

645841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 623.

The product of its digits is 3840, while the sum is 28.

The square root of 645841 is about 803.6423333797. The cubic root of 645841 is about 86.4387618286.

The spelling of 645841 in words is "six hundred forty-five thousand, eight hundred forty-one".