81106042 has 4 divisors (see below), whose sum is σ = 121659066. Its totient is φ = 40553020.

The previous prime is 81106037. The next prime is 81106057. The reversal of 81106042 is 24060118.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 79762761 + 1343281 = 8931^2 + 1159^2 .

It is a Smith number, since the sum of its digits (22) 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 as a sum of consecutive naturals, namely, 20276509 + ... + 20276512.

Almost surely, 2^81106042 is an apocalyptic number.

81106042 is a deficient number, since it is larger than the sum of its proper divisors (40553024).

81106042 is a wasteful number, since it uses less digits than its factorization.

81106042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40553023.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 81106042 is about 9005.8892953445. The cubic root of 81106042 is about 432.8636023723.

The spelling of 81106042 in words is "eighty-one million, one hundred six thousand, forty-two".