251969 has 2 divisors, whose sum is σ = 251970. Its totient is φ = 251968.

The previous prime is 251947. The next prime is 251971. The reversal of 251969 is 969152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207025 + 44944 = 455^2 + 212^2 .

It is a cyclic number.

It is not a de Polignac number, because 251969 - 2¹² = 247873 is a prime.

It is a super-2 number, since 2×251969² = 126976753922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 251971, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (251939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125984 + 125985.

It is an arithmetic number, because the mean of its divisors is an integer number (125985).

2²⁵¹⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

251969 is a deficient number, since it is larger than the sum of its proper divisors (1).

251969 is an equidigital number, since it uses as much as digits as its factorization.

251969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4860, while the sum is 32.

The square root of 251969 is about 501.9651382317. The cubic root of 251969 is about 63.1610058287.

The spelling of 251969 in words is "two hundred fifty-one thousand, nine hundred sixty-nine".