81428442 has 8 divisors (see below), whose sum is σ = 162856896. Its totient is φ = 27142812.

The previous prime is 81428407. The next prime is 81428467. The reversal of 81428442 is 24482418.

It is a sphenic number, since it is the product of 3 distinct primes.

81428442 is an admirable number.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6785698 + ... + 6785709.

It is an arithmetic number, because the mean of its divisors is an integer number (20357112).

Almost surely, 2^81428442 is an apocalyptic number.

81428442 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81428442 is a wasteful number, since it uses less digits than its factorization.

81428442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13571412.

The product of its digits is 16384, while the sum is 33.

The square root of 81428442 is about 9023.7709412418. The cubic root of 81428442 is about 433.4363945530.

The spelling of 81428442 in words is "eighty-one million, four hundred twenty-eight thousand, four hundred forty-two".