251261849 has 4 divisors (see below), whose sum is σ = 251419236. Its totient is φ = 251104464.

The previous prime is 251261827. The next prime is 251261861. The reversal of 251261849 is 948162152.

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

It can be written as a sum of positive squares in 2 ways, for example, as 108889225 + 142372624 = 10435^2 + 11932^2 .

It is a cyclic number.

It is not a de Polignac number, because 251261849 - 2²⁰ = 250213273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251261869) 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, 76274 + ... + 79499.

It is an arithmetic number, because the mean of its divisors is an integer number (62854809).

Almost surely, 2^251261849 is an apocalyptic number.

It is an amenable number.

251261849 is a deficient number, since it is larger than the sum of its proper divisors (157387).

251261849 is a wasteful number, since it uses less digits than its factorization.

251261849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157386.

The product of its digits is 34560, while the sum is 38.

The square root of 251261849 is about 15851.2412447732. The cubic root of 251261849 is about 631.0186334529.

The spelling of 251261849 in words is "two hundred fifty-one million, two hundred sixty-one thousand, eight hundred forty-nine".