81363491623 has 4 divisors (see below), whose sum is σ = 81420271488. Its totient is φ = 81306711760.

The previous prime is 81363491617. The next prime is 81363491663. The reversal of 81363491623 is 32619436318.

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 81363491623 - 2¹³ = 81363483431 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 (81363491663) 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, 28387783 + ... + 28390648.

It is an arithmetic number, because the mean of its divisors is an integer number (20355067872).

Almost surely, 2^81363491623 is an apocalyptic number.

81363491623 is a deficient number, since it is larger than the sum of its proper divisors (56779865).

81363491623 is a wasteful number, since it uses less digits than its factorization.

81363491623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56779864.

The product of its digits is 559872, while the sum is 46.

The spelling of 81363491623 in words is "eighty-one billion, three hundred sixty-three million, four hundred ninety-one thousand, six hundred twenty-three".