86561999 has 2 divisors, whose sum is σ = 86562000. Its totient is φ = 86561998.

The previous prime is 86561971. The next prime is 86562001. The reversal of 86561999 is 99916568.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 86561999 - 2⁸ = 86561743 is a prime.

Together with 86562001, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 86561999.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (86561939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43280999 + 43281000.

It is an arithmetic number, because the mean of its divisors is an integer number (43281000).

Almost surely, 2^86561999 is an apocalyptic number.

86561999 is a deficient number, since it is larger than the sum of its proper divisors (1).

86561999 is an equidigital number, since it uses as much as digits as its factorization.

86561999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1049760, while the sum is 53.

The square root of 86561999 is about 9303.8701087236. The cubic root of 86561999 is about 442.3599079865.

The spelling of 86561999 in words is "eighty-six million, five hundred sixty-one thousand, nine hundred ninety-nine".