81171151 has 4 divisors (see below), whose sum is σ = 81196072. Its totient is φ = 81146232.

The previous prime is 81171149. The next prime is 81171179. The reversal of 81171151 is 15117118.

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 81171151 - 2¹ = 81171149 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 (81171121) 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, 6681 + ... + 14386.

It is an arithmetic number, because the mean of its divisors is an integer number (20299018).

Almost surely, 2^81171151 is an apocalyptic number.

81171151 is a deficient number, since it is larger than the sum of its proper divisors (24921).

81171151 is a wasteful number, since it uses less digits than its factorization.

81171151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24920.

The product of its digits is 280, while the sum is 25.

The square root of 81171151 is about 9009.5033714406. The cubic root of 81171151 is about 432.9794004782.

Adding to 81171151 its reverse (15117118), we get a palindrome (96288269).

The spelling of 81171151 in words is "eighty-one million, one hundred seventy-one thousand, one hundred fifty-one".