645236851 has 8 divisors (see below), whose sum is σ = 752463200. Its totient is φ = 553059864.

The previous prime is 645236849. The next prime is 645236899. The reversal of 645236851 is 158632546.

645236851 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645236851 - 2¹ = 645236849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645236551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 940236 + ... + 940921.

It is an arithmetic number, because the mean of its divisors is an integer number (94057900).

Almost surely, 2^645236851 is an apocalyptic number.

645236851 is a deficient number, since it is larger than the sum of its proper divisors (107226349).

645236851 is an equidigital number, since it uses as much as digits as its factorization.

645236851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1881178 (or 1881164 counting only the distinct ones).

The product of its digits is 172800, while the sum is 40.

The square root of 645236851 is about 25401.5127699120. The cubic root of 645236851 is about 864.1180050548.

The spelling of 645236851 in words is "six hundred forty-five million, two hundred thirty-six thousand, eight hundred fifty-one".