249945991 has 4 divisors (see below), whose sum is σ = 260813232. Its totient is φ = 239078752.

The previous prime is 249945973. The next prime is 249946003. The reversal of 249945991 is 199549942.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 249945991 - 2⁷ = 249945863 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 (249945911) 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, 5433586 + ... + 5433631.

It is an arithmetic number, because the mean of its divisors is an integer number (65203308).

Almost surely, 2^249945991 is an apocalyptic number.

249945991 is a deficient number, since it is larger than the sum of its proper divisors (10867241).

249945991 is a wasteful number, since it uses less digits than its factorization.

249945991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10867240.

The product of its digits is 1049760, while the sum is 52.

The square root of 249945991 is about 15809.6802940477. The cubic root of 249945991 is about 629.9151569629.

The spelling of 249945991 in words is "two hundred forty-nine million, nine hundred forty-five thousand, nine hundred ninety-one".