251436121 has 2 divisors, whose sum is σ = 251436122. Its totient is φ = 251436120.

The previous prime is 251436113. The next prime is 251436131. The reversal of 251436121 is 121634152.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 139499721 + 111936400 = 11811^2 + 10580^2 .

It is a cyclic number.

It is not a de Polignac number, because 251436121 - 2³ = 251436113 is a prime.

It is not a weakly prime, because it can be changed into another prime (251436131) 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, 125718060 + 125718061.

It is an arithmetic number, because the mean of its divisors is an integer number (125718061).

Almost surely, 2^251436121 is an apocalyptic number.

It is an amenable number.

251436121 is a deficient number, since it is larger than the sum of its proper divisors (1).

251436121 is an equidigital number, since it uses as much as digits as its factorization.

251436121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 251436121 is about 15856.7374008653. The cubic root of 251436121 is about 631.1644885508.

The spelling of 251436121 in words is "two hundred fifty-one million, four hundred thirty-six thousand, one hundred twenty-one".