645881333 has 2 divisors, whose sum is σ = 645881334. Its totient is φ = 645881332.

The previous prime is 645881329. The next prime is 645881381. The reversal of 645881333 is 333188546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 607031044 + 38850289 = 24638^2 + 6233^2 .

It is a cyclic number.

It is not a de Polignac number, because 645881333 - 2² = 645881329 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645881393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322940666 + 322940667.

It is an arithmetic number, because the mean of its divisors is an integer number (322940667).

Almost surely, 2^645881333 is an apocalyptic number.

It is an amenable number.

645881333 is a deficient number, since it is larger than the sum of its proper divisors (1).

645881333 is an equidigital number, since it uses as much as digits as its factorization.

645881333 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 207360, while the sum is 41.

The square root of 645881333 is about 25414.1955017270. The cubic root of 645881333 is about 864.4056116823.

The spelling of 645881333 in words is "six hundred forty-five million, eight hundred eighty-one thousand, three hundred thirty-three".