81228042 has 64 divisors (see below), whose sum is σ = 215285760. Its totient is φ = 22196592.

The previous prime is 81228041. The next prime is 81228071. The reversal of 81228042 is 24082218.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 81227997 and 81228015.

It is not an unprimeable number, because it can be changed into a prime (81228041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4023 + ... + 13365.

It is an arithmetic number, because the mean of its divisors is an integer number (3363840).

Almost surely, 2^81228042 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81228042, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107642880).

81228042 is an abundant number, since it is smaller than the sum of its proper divisors (134057718).

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

81228042 is a wasteful number, since it uses less digits than its factorization.

81228042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9384 (or 9378 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 81228042 is about 9012.6600956654. The cubic root of 81228042 is about 433.0805319689.

The spelling of 81228042 in words is "eighty-one million, two hundred twenty-eight thousand, forty-two".