81549167 has 4 divisors (see below), whose sum is σ = 93199056. Its totient is φ = 69899280.

The previous prime is 81549157. The next prime is 81549173. The reversal of 81549167 is 76194518.

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 81549167 - 2¹⁸ = 81287023 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 (81549107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5824934 + ... + 5824947.

It is an arithmetic number, because the mean of its divisors is an integer number (23299764).

Almost surely, 2^81549167 is an apocalyptic number.

81549167 is a deficient number, since it is larger than the sum of its proper divisors (11649889).

81549167 is a wasteful number, since it uses less digits than its factorization.

81549167 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11649888.

The product of its digits is 60480, while the sum is 41.

The square root of 81549167 is about 9030.4577403363. The cubic root of 81549167 is about 433.6504916142.

The spelling of 81549167 in words is "eighty-one million, five hundred forty-nine thousand, one hundred sixty-seven".