86820991 has 2 divisors, whose sum is σ = 86820992. Its totient is φ = 86820990.

The previous prime is 86820971. The next prime is 86821019. The reversal of 86820991 is 19902868.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 86820991 - 2¹³ = 86812799 is a prime.

It is a super-3 number, since 3×86820991³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (86820901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43410495 + 43410496.

It is an arithmetic number, because the mean of its divisors is an integer number (43410496).

Almost surely, 2^86820991 is an apocalyptic number.

86820991 is a deficient number, since it is larger than the sum of its proper divisors (1).

86820991 is an equidigital number, since it uses as much as digits as its factorization.

86820991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 43.

The square root of 86820991 is about 9317.7782223017. The cubic root of 86820991 is about 442.8006464424.

The spelling of 86820991 in words is "eighty-six million, eight hundred twenty thousand, nine hundred ninety-one".