87731287261 has 2 divisors, whose sum is σ = 87731287262. Its totient is φ = 87731287260.

The previous prime is 87731287219. The next prime is 87731287277. The reversal of 87731287261 is 16278213778.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80375652036 + 7355635225 = 283506^2 + 85765^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87731287261 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 87731287199 and 87731287208.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87731237261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43865643630 + 43865643631.

It is an arithmetic number, because the mean of its divisors is an integer number (43865643631).

Almost surely, 2^87731287261 is an apocalyptic number.

It is an amenable number.

87731287261 is a deficient number, since it is larger than the sum of its proper divisors (1).

87731287261 is an equidigital number, since it uses as much as digits as its factorization.

87731287261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1580544, while the sum is 52.

The spelling of 87731287261 in words is "eighty-seven billion, seven hundred thirty-one million, two hundred eighty-seven thousand, two hundred sixty-one".