645241 has 4 divisors (see below), whose sum is σ = 646912. Its totient is φ = 643572.

The previous prime is 645233. The next prime is 645257. The reversal of 645241 is 142546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645241 - 2³ = 645233 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645041) 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, 76 + ... + 1138.

It is an arithmetic number, because the mean of its divisors is an integer number (161728).

2⁶⁴⁵²⁴¹ is an apocalyptic number.

It is an amenable number.

645241 is a deficient number, since it is larger than the sum of its proper divisors (1671).

645241 is a wasteful number, since it uses less digits than its factorization.

645241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1670.

The product of its digits is 960, while the sum is 22.

The square root of 645241 is about 803.2689462440. The cubic root of 645241 is about 86.4119857201.

Adding to 645241 its reverse (142546), we get a palindrome (787787).

The spelling of 645241 in words is "six hundred forty-five thousand, two hundred forty-one".