81066427738 has 4 divisors (see below), whose sum is σ = 121599641610. Its totient is φ = 40533213868.

The previous prime is 81066427699. The next prime is 81066427753. The reversal of 81066427738 is 83772466018.

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., 57526583409 + 23539844329 = 239847^2 + 153427^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20266606933 + ... + 20266606936.

Almost surely, 2^81066427738 is an apocalyptic number.

81066427738 is a deficient number, since it is larger than the sum of its proper divisors (40533213872).

81066427738 is a wasteful number, since it uses less digits than its factorization.

81066427738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40533213871.

The product of its (nonzero) digits is 2709504, while the sum is 52.

The spelling of 81066427738 in words is "eighty-one billion, sixty-six million, four hundred twenty-seven thousand, seven hundred thirty-eight".