87936781 has 2 divisors, whose sum is σ = 87936782. Its totient is φ = 87936780.

The previous prime is 87936743. The next prime is 87936809. The reversal of 87936781 is 18763978.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47817225 + 40119556 = 6915^2 + 6334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87936781 is a prime.

It is a super-2 number, since 2×87936781² = 15465754905283922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87936281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43968390 + 43968391.

It is an arithmetic number, because the mean of its divisors is an integer number (43968391).

Almost surely, 2^87936781 is an apocalyptic number.

It is an amenable number.

87936781 is a deficient number, since it is larger than the sum of its proper divisors (1).

87936781 is an equidigital number, since it uses as much as digits as its factorization.

87936781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 508032, while the sum is 49.

The square root of 87936781 is about 9377.4613302322. The cubic root of 87936781 is about 444.6894791145.

The spelling of 87936781 in words is "eighty-seven million, nine hundred thirty-six thousand, seven hundred eighty-one".