261261787 has 2 divisors, whose sum is σ = 261261788. Its totient is φ = 261261786.

The previous prime is 261261757. The next prime is 261261811. The reversal of 261261787 is 787162162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261261787 - 2¹⁵ = 261229019 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261261757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130630893 + 130630894.

It is an arithmetic number, because the mean of its divisors is an integer number (130630894).

Almost surely, 2^261261787 is an apocalyptic number.

261261787 is a deficient number, since it is larger than the sum of its proper divisors (1).

261261787 is an equidigital number, since it uses as much as digits as its factorization.

261261787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56448, while the sum is 40.

The square root of 261261787 is about 16163.5944950373. The cubic root of 261261787 is about 639.2812463266.

The spelling of 261261787 in words is "two hundred sixty-one million, two hundred sixty-one thousand, seven hundred eighty-seven".