261787 has 2 divisors, whose sum is σ = 261788. Its totient is φ = 261786.

The previous prime is 261773. The next prime is 261791. The reversal of 261787 is 787162.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261787 is a prime.

It is not a weakly prime, because it can be changed into another prime (261707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130893 + 130894.

It is an arithmetic number, because the mean of its divisors is an integer number (130894).

2²⁶¹⁷⁸⁷ is an apocalyptic number.

261787 is a deficient number, since it is larger than the sum of its proper divisors (1).

261787 is an equidigital number, since it uses as much as digits as its factorization.

261787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4704, while the sum is 31.

The square root of 261787 is about 511.6512484105. The cubic root of 261787 is about 63.9709340672.

It can be divided in two parts, 2617 and 87, that added together give a square (2704 = 52²).

The spelling of 261787 in words is "two hundred sixty-one thousand, seven hundred eighty-seven".