86821989 has 4 divisors (see below), whose sum is σ = 115762656. Its totient is φ = 57881324.

The previous prime is 86821967. The next prime is 86821991. The reversal of 86821989 is 98912868.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 86821989 - 2⁸ = 86821733 is a prime.

It is a super-2 number, since 2×86821989² = 15076115547832242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (86821949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14470329 + ... + 14470334.

It is an arithmetic number, because the mean of its divisors is an integer number (28940664).

Almost surely, 2^86821989 is an apocalyptic number.

It is an amenable number.

86821989 is a deficient number, since it is larger than the sum of its proper divisors (28940667).

86821989 is a wasteful number, since it uses less digits than its factorization.

86821989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28940666.

The product of its digits is 497664, while the sum is 51.

The square root of 86821989 is about 9317.8317756869. The cubic root of 86821989 is about 442.8023430880.

The spelling of 86821989 in words is "eighty-six million, eight hundred twenty-one thousand, nine hundred eighty-nine".