86165721 has 8 divisors (see below), whose sum is σ = 127652960. Its totient is φ = 57443796.

The previous prime is 86165713. The next prime is 86165731. The reversal of 86165721 is 12756168.

86165721 is a `hidden beast` number, since 86 + 1 + 6 + 572 + 1 = 666.

It is not a de Polignac number, because 86165721 - 2³ = 86165713 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (86165731) 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, 1595635 + ... + 1595688.

It is an arithmetic number, because the mean of its divisors is an integer number (15956620).

Almost surely, 2^86165721 is an apocalyptic number.

It is an amenable number.

86165721 is a deficient number, since it is larger than the sum of its proper divisors (41487239).

86165721 is a wasteful number, since it uses less digits than its factorization.

86165721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3191332 (or 3191326 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 86165721 is about 9282.5492726944. The cubic root of 86165721 is about 441.6838388640.

The spelling of 86165721 in words is "eighty-six million, one hundred sixty-five thousand, seven hundred twenty-one".