81251159 has 4 divisors (see below), whose sum is σ = 88637640. Its totient is φ = 73864680.

The previous prime is 81251153. The next prime is 81251227. The reversal of 81251159 is 95115218.

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 81251159 - 2¹⁶ = 81185623 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 (81251153) 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, 3693224 + ... + 3693245.

It is an arithmetic number, because the mean of its divisors is an integer number (22159410).

Almost surely, 2^81251159 is an apocalyptic number.

81251159 is a deficient number, since it is larger than the sum of its proper divisors (7386481).

81251159 is a wasteful number, since it uses less digits than its factorization.

81251159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7386480.

The product of its digits is 3600, while the sum is 32.

The square root of 81251159 is about 9013.9424781835. The cubic root of 81251159 is about 433.1216120886.

The spelling of 81251159 in words is "eighty-one million, two hundred fifty-one thousand, one hundred fifty-nine".