81672386786 has 8 divisors (see below), whose sum is σ = 122521134684. Its totient is φ = 40832008560.

The previous prime is 81672386777. The next prime is 81672386827. The reversal of 81672386786 is 68768327618.

It can be written as a sum of positive squares in 2 ways, for example, as 75175220761 + 6497166025 = 274181^2 + 80605^2 .

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

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, 2067965 + ... + 2107088.

Almost surely, 2^81672386786 is an apocalyptic number.

81672386786 is a deficient number, since it is larger than the sum of its proper divisors (40848747898).

81672386786 is a wasteful number, since it uses less digits than its factorization.

81672386786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4184836.

The product of its digits is 32514048, while the sum is 62.

The spelling of 81672386786 in words is "eighty-one billion, six hundred seventy-two million, three hundred eighty-six thousand, seven hundred eighty-six".