81236610 has 216 divisors, whose sum is σ = 268493940. Its totient is φ = 16982784.

The previous prime is 81236587. The next prime is 81236653. The reversal of 81236610 is 1663218.

81236610 is a `hidden beast` number, since 8 + 12 + 36 + 610 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 13816089 + 67420521 = 3717^2 + 8211^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 745236 + ... + 745344.

Almost surely, 2^81236610 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81236610, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134246970).

81236610 is an abundant number, since it is smaller than the sum of its proper divisors (187257330).

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

81236610 is a wasteful number, since it uses less digits than its factorization.

81236610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 139 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 81236610 is about 9013.1354144937. The cubic root of 81236610 is about 433.0957586626.

Adding to 81236610 its reverse (1663218), we get a palindrome (82899828).

The spelling of 81236610 in words is "eighty-one million, two hundred thirty-six thousand, six hundred ten".