81774561013 has 4 divisors (see below), whose sum is σ = 81785531680. Its totient is φ = 81763590348.

The previous prime is 81774560951. The next prime is 81774561047. The reversal of 81774561013 is 31016547718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81774561013 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 (81774561053) 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, 5474145 + ... + 5489062.

It is an arithmetic number, because the mean of its divisors is an integer number (20446382920).

Almost surely, 2^81774561013 is an apocalyptic number.

It is an amenable number.

81774561013 is a deficient number, since it is larger than the sum of its proper divisors (10970667).

81774561013 is a wasteful number, since it uses less digits than its factorization.

81774561013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10970666.

The product of its (nonzero) digits is 141120, while the sum is 43.

The spelling of 81774561013 in words is "eighty-one billion, seven hundred seventy-four million, five hundred sixty-one thousand, thirteen".