81374776786 has 8 divisors (see below), whose sum is σ = 122063643900. Its totient is φ = 40686895488.

The previous prime is 81374776781. The next prime is 81374776787. The reversal of 81374776786 is 68767747318.

It can be written as a sum of positive squares in 2 ways, for example, as 66116351161 + 15258425625 = 257131^2 + 123525^2 .

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

It is not an unprimeable number, because it can be changed into a prime (81374776781) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 15670 + ... + 403726.

Almost surely, 2^81374776786 is an apocalyptic number.

81374776786 is a deficient number, since it is larger than the sum of its proper divisors (40688867114).

81374776786 is a wasteful number, since it uses less digits than its factorization.

81374776786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 492908.

The product of its digits is 66382848, while the sum is 64.

The spelling of 81374776786 in words is "eighty-one billion, three hundred seventy-four million, seven hundred seventy-six thousand, seven hundred eighty-six".