81361888 has 36 divisors (see below), whose sum is σ = 163804032. Its totient is φ = 39780800.

The previous prime is 81361883. The next prime is 81361909. The reversal of 81361888 is 88816318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81361883) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 70113 + ... + 71263.

It is an arithmetic number, because the mean of its divisors is an integer number (4550112).

Almost surely, 2^81361888 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 81361888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81902016).

81361888 is an abundant number, since it is smaller than the sum of its proper divisors (82442144).

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

81361888 is a wasteful number, since it uses less digits than its factorization.

81361888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1255 (or 1200 counting only the distinct ones).

The product of its digits is 73728, while the sum is 43.

The square root of 81361888 is about 9020.0824829932. The cubic root of 81361888 is about 433.3182753479.

The spelling of 81361888 in words is "eighty-one million, three hundred sixty-one thousand, eight hundred eighty-eight".