81285693 has 4 divisors (see below), whose sum is σ = 108380928. Its totient is φ = 54190460.

The previous prime is 81285649. The next prime is 81285697. The reversal of 81285693 is 39658218.

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 81285693 - 2²¹ = 79188541 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81285697) 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, 13547613 + ... + 13547618.

It is an arithmetic number, because the mean of its divisors is an integer number (27095232).

Almost surely, 2^81285693 is an apocalyptic number.

It is an amenable number.

81285693 is a deficient number, since it is larger than the sum of its proper divisors (27095235).

81285693 is a wasteful number, since it uses less digits than its factorization.

81285693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27095234.

The product of its digits is 103680, while the sum is 42.

The square root of 81285693 is about 9015.8578626773. The cubic root of 81285693 is about 433.1829663032.

The spelling of 81285693 in words is "eighty-one million, two hundred eighty-five thousand, six hundred ninety-three".