87981181 has 2 divisors, whose sum is σ = 87981182. Its totient is φ = 87981180.

The previous prime is 87981167. The next prime is 87981199. The reversal of 87981181 is 18118978.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46172025 + 41809156 = 6795^2 + 6466^2 .

It is a cyclic number.

It is not a de Polignac number, because 87981181 - 2⁵ = 87981149 is a prime.

It is a super-2 number, since 2×87981181² = 15481376420309522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87981281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43990590 + 43990591.

It is an arithmetic number, because the mean of its divisors is an integer number (43990591).

Almost surely, 2^87981181 is an apocalyptic number.

It is an amenable number.

87981181 is a deficient number, since it is larger than the sum of its proper divisors (1).

87981181 is an equidigital number, since it uses as much as digits as its factorization.

87981181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32256, while the sum is 43.

The square root of 87981181 is about 9379.8284099444. The cubic root of 87981181 is about 444.7643089736.

The spelling of 87981181 in words is "eighty-seven million, nine hundred eighty-one thousand, one hundred eighty-one".