81869183 has 4 divisors (see below), whose sum is σ = 89311848. Its totient is φ = 74426520.

The previous prime is 81869147. The next prime is 81869189. The reversal of 81869183 is 38196818.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81869183 - 2¹⁰ = 81868159 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81869189) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3721316 + ... + 3721337.

It is an arithmetic number, because the mean of its divisors is an integer number (22327962).

Almost surely, 2^81869183 is an apocalyptic number.

81869183 is a deficient number, since it is larger than the sum of its proper divisors (7442665).

81869183 is a wasteful number, since it uses less digits than its factorization.

81869183 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7442664.

The product of its digits is 82944, while the sum is 44.

The square root of 81869183 is about 9048.1590945341. The cubic root of 81869183 is about 434.2169963296.

The spelling of 81869183 in words is "eighty-one million, eight hundred sixty-nine thousand, one hundred eighty-three".