81155867 has 4 divisors (see below), whose sum is σ = 87398640. Its totient is φ = 74913096.

The previous prime is 81155839. The next prime is 81155869. The reversal of 81155867 is 76855118.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76855118 = 2 ⋅38427559.

It is a cyclic number.

It is not a de Polignac number, because 81155867 - 2⁸ = 81155611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81155869) 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, 3121367 + ... + 3121392.

It is an arithmetic number, because the mean of its divisors is an integer number (21849660).

Almost surely, 2^81155867 is an apocalyptic number.

81155867 is a deficient number, since it is larger than the sum of its proper divisors (6242773).

81155867 is a wasteful number, since it uses less digits than its factorization.

81155867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6242772.

The product of its digits is 67200, while the sum is 41.

The square root of 81155867 is about 9008.6551160537. The cubic root of 81155867 is about 432.9522230370.

The spelling of 81155867 in words is "eighty-one million, one hundred fifty-five thousand, eight hundred sixty-seven".