251601247 has 4 divisors (see below), whose sum is σ = 252066856. Its totient is φ = 251135640.

The previous prime is 251601223. The next prime is 251601257. The reversal of 251601247 is 742106152.

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 251601247 - 2¹¹ = 251599199 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 (251601257) 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, 231993 + ... + 233074.

It is an arithmetic number, because the mean of its divisors is an integer number (63016714).

Almost surely, 2^251601247 is an apocalyptic number.

251601247 is a deficient number, since it is larger than the sum of its proper divisors (465609).

251601247 is an equidigital number, since it uses as much as digits as its factorization.

251601247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 465608.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 251601247 is about 15861.9433550874. The cubic root of 251601247 is about 631.3026268316.

Adding to 251601247 its reverse (742106152), we get a palindrome (993707399).

The spelling of 251601247 in words is "two hundred fifty-one million, six hundred one thousand, two hundred forty-seven".