81374776783 has 4 divisors (see below), whose sum is σ = 81377446320. Its totient is φ = 81372107248.

The previous prime is 81374776781. The next prime is 81374776787. The reversal of 81374776783 is 38767747318.

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

It is a cyclic number.

It is not a de Polignac number, because 81374776783 - 2¹ = 81374776781 is a prime.

It is a Duffinian number.

It is a congruent number.

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 (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1288510 + ... + 1350187.

It is an arithmetic number, because the mean of its divisors is an integer number (20344361580).

Almost surely, 2^81374776783 is an apocalyptic number.

81374776783 is a deficient number, since it is larger than the sum of its proper divisors (2669537).

81374776783 is a wasteful number, since it uses less digits than its factorization.

81374776783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2669536.

The product of its digits is 33191424, while the sum is 61.

The spelling of 81374776783 in words is "eighty-one billion, three hundred seventy-four million, seven hundred seventy-six thousand, seven hundred eighty-three".