87781905161 has 2 divisors, whose sum is σ = 87781905162. Its totient is φ = 87781905160.

The previous prime is 87781905103. The next prime is 87781905173. The reversal of 87781905161 is 16150918778.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67849830400 + 19932074761 = 260480^2 + 141181^2 .

It is a cyclic number.

It is not a de Polignac number, because 87781905161 - 2²⁶ = 87714796297 is a prime.

It is not a weakly prime, because it can be changed into another prime (87781908161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43890952580 + 43890952581.

It is an arithmetic number, because the mean of its divisors is an integer number (43890952581).

Almost surely, 2^87781905161 is an apocalyptic number.

It is an amenable number.

87781905161 is a deficient number, since it is larger than the sum of its proper divisors (1).

87781905161 is an equidigital number, since it uses as much as digits as its factorization.

87781905161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 846720, while the sum is 53.

The spelling of 87781905161 in words is "eighty-seven billion, seven hundred eighty-one million, nine hundred five thousand, one hundred sixty-one".