81159776 has 12 divisors (see below), whose sum is σ = 159783372. Its totient is φ = 40579872.

The previous prime is 81159769. The next prime is 81159779. The reversal of 81159776 is 67795118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81159779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1268090 + ... + 1268153.

It is an arithmetic number, because the mean of its divisors is an integer number (13315281).

Almost surely, 2^81159776 is an apocalyptic number.

It is an amenable number.

81159776 is a deficient number, since it is larger than the sum of its proper divisors (78623596).

81159776 is a wasteful number, since it uses less digits than its factorization.

81159776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2536253 (or 2536245 counting only the distinct ones).

The product of its digits is 105840, while the sum is 44.

The square root of 81159776 is about 9008.8720714638. The cubic root of 81159776 is about 432.9591742004.

The spelling of 81159776 in words is "eighty-one million, one hundred fifty-nine thousand, seven hundred seventy-six".