251949 has 4 divisors (see below), whose sum is σ = 335936. Its totient is φ = 167964.

The previous prime is 251947. The next prime is 251969. The reversal of 251949 is 949152.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 251949 - 2¹ = 251947 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251941) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41989 + ... + 41994.

It is an arithmetic number, because the mean of its divisors is an integer number (83984).

2²⁵¹⁹⁴⁹ is an apocalyptic number.

It is an amenable number.

251949 is a deficient number, since it is larger than the sum of its proper divisors (83987).

251949 is an equidigital number, since it uses as much as digits as its factorization.

251949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83986.

The product of its digits is 3240, while the sum is 30.

The square root of 251949 is about 501.9452161342. The cubic root of 251949 is about 63.1593346528.

The spelling of 251949 in words is "two hundred fifty-one thousand, nine hundred forty-nine".