249679891 has 2 divisors, whose sum is σ = 249679892. Its totient is φ = 249679890.

The previous prime is 249679877. The next prime is 249679909. The reversal of 249679891 is 198976942.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 249679891 - 2⁹ = 249679379 is a prime.

It is not a weakly prime, because it can be changed into another prime (249679291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124839945 + 124839946.

It is an arithmetic number, because the mean of its divisors is an integer number (124839946).

Almost surely, 2^249679891 is an apocalyptic number.

249679891 is a deficient number, since it is larger than the sum of its proper divisors (1).

249679891 is an equidigital number, since it uses as much as digits as its factorization.

249679891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1959552, while the sum is 55.

The square root of 249679891 is about 15801.2623229918. The cubic root of 249679891 is about 629.6915353952.

The spelling of 249679891 in words is "two hundred forty-nine million, six hundred seventy-nine thousand, eight hundred ninety-one".