261751591 has 2 divisors, whose sum is σ = 261751592. Its totient is φ = 261751590.

The previous prime is 261751573. The next prime is 261751627. The reversal of 261751591 is 195157162.

261751591 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261751591 - 2⁵ = 261751559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261751591.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261751561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130875795 + 130875796.

It is an arithmetic number, because the mean of its divisors is an integer number (130875796).

Almost surely, 2^261751591 is an apocalyptic number.

261751591 is a deficient number, since it is larger than the sum of its proper divisors (1).

261751591 is an equidigital number, since it uses as much as digits as its factorization.

261751591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18900, while the sum is 37.

The square root of 261751591 is about 16178.7388569072. The cubic root of 261751591 is about 639.6804972617.

The spelling of 261751591 in words is "two hundred sixty-one million, seven hundred fifty-one thousand, five hundred ninety-one".