251136401 has 2 divisors, whose sum is σ = 251136402. Its totient is φ = 251136400.

The previous prime is 251136397. The next prime is 251136407. The reversal of 251136401 is 104631152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127148176 + 123988225 = 11276^2 + 11135^2 .

It is a cyclic number.

It is not a de Polignac number, because 251136401 - 2² = 251136397 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (251136407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125568200 + 125568201.

It is an arithmetic number, because the mean of its divisors is an integer number (125568201).

Almost surely, 2^251136401 is an apocalyptic number.

It is an amenable number.

251136401 is a deficient number, since it is larger than the sum of its proper divisors (1).

251136401 is an equidigital number, since it uses as much as digits as its factorization.

251136401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 251136401 is about 15847.2837104660. The cubic root of 251136401 is about 630.9135993306.

Adding to 251136401 its reverse (104631152), we get a palindrome (355767553).

The spelling of 251136401 in words is "two hundred fifty-one million, one hundred thirty-six thousand, four hundred one".