251197381 has 2 divisors, whose sum is σ = 251197382. Its totient is φ = 251197380.

The previous prime is 251197379. The next prime is 251197459. The reversal of 251197381 is 183791152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 250937281 + 260100 = 15841^2 + 510^2 .

It is a cyclic number.

It is not a de Polignac number, because 251197381 - 2¹ = 251197379 is a prime.

It is a super-2 number, since 2×251197381² = 126200248442518322, which contains 22 as substring.

Together with 251197379, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 251197381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251197301) 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 as a sum of consecutive naturals, namely, 125598690 + 125598691.

It is an arithmetic number, because the mean of its divisors is an integer number (125598691).

Almost surely, 2^251197381 is an apocalyptic number.

It is an amenable number.

251197381 is a deficient number, since it is larger than the sum of its proper divisors (1).

251197381 is an equidigital number, since it uses as much as digits as its factorization.

251197381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15120, while the sum is 37.

The square root of 251197381 is about 15849.2075827153. The cubic root of 251197381 is about 630.9646605568.

The spelling of 251197381 in words is "two hundred fifty-one million, one hundred ninety-seven thousand, three hundred eighty-one".