81776172046 has 4 divisors (see below), whose sum is σ = 122664258072. Its totient is φ = 40888086022.

The previous prime is 81776172031. The next prime is 81776172073. The reversal of 81776172046 is 64027167718.

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

It is a super-2 number, since 2×81776172046² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20444043010 + ... + 20444043013.

It is an arithmetic number, because the mean of its divisors is an integer number (30666064518).

Almost surely, 2^81776172046 is an apocalyptic number.

81776172046 is a deficient number, since it is larger than the sum of its proper divisors (40888086026).

81776172046 is a wasteful number, since it uses less digits than its factorization.

81776172046 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40888086025.

The product of its (nonzero) digits is 790272, while the sum is 49.

The spelling of 81776172046 in words is "eighty-one billion, seven hundred seventy-six million, one hundred seventy-two thousand, forty-six".