86691989 has 2 divisors, whose sum is σ = 86691990. Its totient is φ = 86691988.

The previous prime is 86691977. The next prime is 86692009. The reversal of 86691989 is 98919668.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80102500 + 6589489 = 8950^2 + 2567^2 .

It is a cyclic number.

It is not a de Polignac number, because 86691989 - 2²⁴ = 69914773 is a prime.

It is a super-2 number, since 2×86691989² = 15031001913552242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (86693989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43345994 + 43345995.

It is an arithmetic number, because the mean of its divisors is an integer number (43345995).

Almost surely, 2^86691989 is an apocalyptic number.

It is an amenable number.

86691989 is a deficient number, since it is larger than the sum of its proper divisors (1).

86691989 is an equidigital number, since it uses as much as digits as its factorization.

86691989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1679616, while the sum is 56.

The square root of 86691989 is about 9310.8532906496. The cubic root of 86691989 is about 442.5812276008.

The spelling of 86691989 in words is "eighty-six million, six hundred ninety-one thousand, nine hundred eighty-nine".