251511563 has 2 divisors, whose sum is σ = 251511564. Its totient is φ = 251511562.

The previous prime is 251511529. The next prime is 251511571. The reversal of 251511563 is 365115152.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 251511563 - 2¹⁸ = 251249419 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (251511263) 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, 125755781 + 125755782.

It is an arithmetic number, because the mean of its divisors is an integer number (125755782).

Almost surely, 2^251511563 is an apocalyptic number.

251511563 is a deficient number, since it is larger than the sum of its proper divisors (1).

251511563 is an equidigital number, since it uses as much as digits as its factorization.

251511563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4500, while the sum is 29.

The square root of 251511563 is about 15859.1160850786. The cubic root of 251511563 is about 631.2276080284.

The spelling of 251511563 in words is "two hundred fifty-one million, five hundred eleven thousand, five hundred sixty-three".