81601156 has 48 divisors (see below), whose sum is σ = 186109056. Its totient is φ = 30380544.

The previous prime is 81601151. The next prime is 81601199. The reversal of 81601156 is 65110618.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (81601151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 406 + ... + 12781.

It is an arithmetic number, because the mean of its divisors is an integer number (3877272).

Almost surely, 2^81601156 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81601156, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93054528).

81601156 is an abundant number, since it is smaller than the sum of its proper divisors (104507900).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81601156 is a wasteful number, since it uses less digits than its factorization.

81601156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13228 (or 13226 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 81601156 is about 9033.3358179578. The cubic root of 81601156 is about 433.7426252598.

It can be divided in two parts, 8160 and 1156, that added together give a triangular number (9316 = T₁₃₆).

The spelling of 81601156 in words is "eighty-one million, six hundred one thousand, one hundred fifty-six".