249949991 has 4 divisors (see below), whose sum is σ = 250000800. Its totient is φ = 249899184.

The previous prime is 249949979. The next prime is 249950023. The reversal of 249949991 is 199949942.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-249949991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (249949951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17126 + ... + 28163.

It is an arithmetic number, because the mean of its divisors is an integer number (62500200).

Almost surely, 2^249949991 is an apocalyptic number.

249949991 is a deficient number, since it is larger than the sum of its proper divisors (50809).

249949991 is an equidigital number, since it uses as much as digits as its factorization.

249949991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50808.

The product of its digits is 1889568, while the sum is 56.

The square root of 249949991 is about 15809.8067983135. The cubic root of 249949991 is about 629.9185172184.

The spelling of 249949991 in words is "two hundred forty-nine million, nine hundred forty-nine thousand, nine hundred ninety-one".