81122040 has 128 divisors (see below), whose sum is σ = 279244800. Its totient is φ = 20926080.

The previous prime is 81122033. The next prime is 81122159. The reversal of 81122040 is 4022118.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 32269 + ... + 34691.

It is an arithmetic number, because the mean of its divisors is an integer number (2181600).

Almost surely, 2^81122040 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 81122040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139622400).

81122040 is an abundant number, since it is smaller than the sum of its proper divisors (198122760).

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

81122040 is a wasteful number, since it uses less digits than its factorization.

81122040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2474 (or 2464 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 81122040 is about 9006.7774481221. Note that the first 3 decimals coincide. The cubic root of 81122040 is about 432.8920609864.

Adding to 81122040 its reverse (4022118), we get a palindrome (85144158).

The spelling of 81122040 in words is "eighty-one million, one hundred twenty-two thousand, forty".