645940843 has 4 divisors (see below), whose sum is σ = 646358328. Its totient is φ = 645523360.

The previous prime is 645940837. The next prime is 645940849. The reversal of 645940843 is 348049546.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (645940837) and next prime (645940849).

It is a cyclic number.

It is not a de Polignac number, because 645940843 - 2⁵ = 645940811 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645940843.

It is not an unprimeable number, because it can be changed into a prime (645940849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 206413 + ... + 209518.

It is an arithmetic number, because the mean of its divisors is an integer number (161589582).

Almost surely, 2^645940843 is an apocalyptic number.

645940843 is a deficient number, since it is larger than the sum of its proper divisors (417485).

645940843 is a wasteful number, since it uses less digits than its factorization.

645940843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 417484.

The product of its (nonzero) digits is 414720, while the sum is 43.

The square root of 645940843 is about 25415.3662771167. The cubic root of 645940843 is about 864.4321589729.

The spelling of 645940843 in words is "six hundred forty-five million, nine hundred forty thousand, eight hundred forty-three".