1187287261 has 2 divisors, whose sum is σ = 1187287262. Its totient is φ = 1187287260.

The previous prime is 1187287247. The next prime is 1187287303. The reversal of 1187287261 is 1627827811.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1106826361 + 80460900 = 33269^2 + 8970^2 .

It is an emirp because it is prime and its reverse (1627827811) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1187287261 - 2⁵ = 1187287229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1187287201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 593643630 + 593643631.

It is an arithmetic number, because the mean of its divisors is an integer number (593643631).

Almost surely, 2^1187287261 is an apocalyptic number.

It is an amenable number.

1187287261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1187287261 is an equidigital number, since it uses as much as digits as its factorization.

1187287261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75264, while the sum is 43.

The square root of 1187287261 is about 34457.0350001273. The cubic root of 1187287261 is about 1058.8926554539.

The spelling of 1187287261 in words is "one billion, one hundred eighty-seven million, two hundred eighty-seven thousand, two hundred sixty-one".