645254851 has 2 divisors, whose sum is σ = 645254852. Its totient is φ = 645254850.

The previous prime is 645254849. The next prime is 645254879. The reversal of 645254851 is 158452546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645254851 - 2¹ = 645254849 is a prime.

Together with 645254849, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (645254891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322627425 + 322627426.

It is an arithmetic number, because the mean of its divisors is an integer number (322627426).

Almost surely, 2^645254851 is an apocalyptic number.

645254851 is a deficient number, since it is larger than the sum of its proper divisors (1).

645254851 is an equidigital number, since it uses as much as digits as its factorization.

645254851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 192000, while the sum is 40.

The square root of 645254851 is about 25401.8670770477. The cubic root of 645254851 is about 864.1260403365.

The spelling of 645254851 in words is "six hundred forty-five million, two hundred fifty-four thousand, eight hundred fifty-one".