251397247 has 2 divisors, whose sum is σ = 251397248. Its totient is φ = 251397246.

The previous prime is 251397233. The next prime is 251397257. The reversal of 251397247 is 742793152.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 251397247 - 2⁷ = 251397119 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251397217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125698623 + 125698624.

It is an arithmetic number, because the mean of its divisors is an integer number (125698624).

Almost surely, 2^251397247 is an apocalyptic number.

251397247 is a deficient number, since it is larger than the sum of its proper divisors (1).

251397247 is an equidigital number, since it uses as much as digits as its factorization.

251397247 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 105840, while the sum is 40.

The square root of 251397247 is about 15855.5115653832. The cubic root of 251397247 is about 631.1319592112.

The spelling of 251397247 in words is "two hundred fifty-one million, three hundred ninety-seven thousand, two hundred forty-seven".