249895021 has 2 divisors, whose sum is σ = 249895022. Its totient is φ = 249895020.

The previous prime is 249895007. The next prime is 249895027. The reversal of 249895021 is 120598942.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 249197796 + 697225 = 15786^2 + 835^2 .

It is a cyclic number.

It is not a de Polignac number, because 249895021 - 2⁷ = 249894893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (249895027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124947510 + 124947511.

It is an arithmetic number, because the mean of its divisors is an integer number (124947511).

Almost surely, 2^249895021 is an apocalyptic number.

It is an amenable number.

249895021 is a deficient number, since it is larger than the sum of its proper divisors (1).

249895021 is an equidigital number, since it uses as much as digits as its factorization.

249895021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 249895021 is about 15808.0682248022. The cubic root of 249895021 is about 629.8723357677.

The spelling of 249895021 in words is "two hundred forty-nine million, eight hundred ninety-five thousand, twenty-one".