86191821 has 12 divisors (see below), whose sum is σ = 124962240. Its totient is φ = 57247560.

The previous prime is 86191813. The next prime is 86191829. The reversal of 86191821 is 12819168.

86191821 is a `hidden beast` number, since 8 + 619 + 18 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (86191813) and next prime (86191829).

It is not a de Polignac number, because 86191821 - 2³ = 86191813 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (86191829) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15231 + ... + 20108.

It is an arithmetic number, because the mean of its divisors is an integer number (10413520).

Almost surely, 2^86191821 is an apocalyptic number.

It is an amenable number.

86191821 is a deficient number, since it is larger than the sum of its proper divisors (38770419).

86191821 is a wasteful number, since it uses less digits than its factorization.

86191821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35616 (or 35613 counting only the distinct ones).

The product of its digits is 6912, while the sum is 36.

The square root of 86191821 is about 9283.9550300505. The cubic root of 86191821 is about 441.7284303957.

It can be divided in two parts, 8619 and 1821, that added together give a triangular number (10440 = T₁₄₄).

The spelling of 86191821 in words is "eighty-six million, one hundred ninety-one thousand, eight hundred twenty-one".