81125388 has 120 divisors (see below), whose sum is σ = 225396864. Its totient is φ = 25401600.

The previous prime is 81125371. The next prime is 81125449. The reversal of 81125388 is 88352118.

81125388 is a `hidden beast` number, since 8 + 112 + 538 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

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 39 ways as a sum of consecutive naturals, for example, 411706 + ... + 411902.

Almost surely, 2^81125388 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 81125388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112698432).

81125388 is an abundant number, since it is smaller than the sum of its proper divisors (144271476).

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

81125388 is a wasteful number, since it uses less digits than its factorization.

81125388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285 (or 274 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 81125388 is about 9006.9633062426. The cubic root of 81125388 is about 432.8980162224.

The spelling of 81125388 in words is "eighty-one million, one hundred twenty-five thousand, three hundred eighty-eight".