86731981 has 8 divisors (see below), whose sum is σ = 99754880. Its totient is φ = 73867248.

The previous prime is 86731963. The next prime is 86732027. The reversal of 86731981 is 18913768.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 86731981 - 2⁵ = 86731949 is a prime.

It is a super-2 number, since 2×86731981² = 15044873056368722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (86731921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38361 + ... + 40558.

It is an arithmetic number, because the mean of its divisors is an integer number (12469360).

Almost surely, 2^86731981 is an apocalyptic number.

It is an amenable number.

86731981 is a deficient number, since it is larger than the sum of its proper divisors (13022899).

86731981 is a wasteful number, since it uses less digits than its factorization.

86731981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79083.

The product of its digits is 72576, while the sum is 43.

The square root of 86731981 is about 9313.0006442607. Note that the first 3 decimals coincide. The cubic root of 86731981 is about 442.6492730556.

The spelling of 86731981 in words is "eighty-six million, seven hundred thirty-one thousand, nine hundred eighty-one".