81693867 has 4 divisors (see below), whose sum is σ = 108925160. Its totient is φ = 54462576.

The previous prime is 81693847. The next prime is 81693883. The reversal of 81693867 is 76839618.

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

It is not a de Polignac number, because 81693867 - 2⁶ = 81693803 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81693847) 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, 13615642 + ... + 13615647.

It is an arithmetic number, because the mean of its divisors is an integer number (27231290).

Almost surely, 2^81693867 is an apocalyptic number.

81693867 is a deficient number, since it is larger than the sum of its proper divisors (27231293).

81693867 is a wasteful number, since it uses less digits than its factorization.

81693867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27231292.

The product of its digits is 435456, while the sum is 48.

The square root of 81693867 is about 9038.4659649744. The cubic root of 81693867 is about 433.9068283786.

The spelling of 81693867 in words is "eighty-one million, six hundred ninety-three thousand, eight hundred sixty-seven".