81138360 has 96 divisors (see below), whose sum is σ = 257037840. Its totient is φ = 20487168.

The previous prime is 81138347. The next prime is 81138367. The reversal of 81138360 is 6383118.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81138367) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42384 + ... + 44256.

Almost surely, 2^81138360 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 81138360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128518920).

81138360 is an abundant number, since it is smaller than the sum of its proper divisors (175899480).

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

81138360 is a wasteful number, since it uses less digits than its factorization.

81138360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1925 (or 1902 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 81138360 is about 9007.6833869758. The cubic root of 81138360 is about 432.9210885467.

The spelling of 81138360 in words is "eighty-one million, one hundred thirty-eight thousand, three hundred sixty".