251585513 has 2 divisors, whose sum is σ = 251585514. Its totient is φ = 251585512.

The previous prime is 251585507. The next prime is 251585531. The reversal of 251585513 is 315585152.

Together with next prime (251585531) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 251159104 + 426409 = 15848^2 + 653^2 .

It is a cyclic number.

It is not a de Polignac number, because 251585513 - 2¹² = 251581417 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (251585563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125792756 + 125792757.

It is an arithmetic number, because the mean of its divisors is an integer number (125792757).

Almost surely, 2^251585513 is an apocalyptic number.

It is an amenable number.

251585513 is a deficient number, since it is larger than the sum of its proper divisors (1).

251585513 is an equidigital number, since it uses as much as digits as its factorization.

251585513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30000, while the sum is 35.

The square root of 251585513 is about 15861.4473803622. The cubic root of 251585513 is about 631.2894669570.

The spelling of 251585513 in words is "two hundred fifty-one million, five hundred eighty-five thousand, five hundred thirteen".