81749433023 has 4 divisors (see below), whose sum is σ = 81750386688. Its totient is φ = 81748479360.

The previous prime is 81749433019. The next prime is 81749433053. The reversal of 81749433023 is 32033494718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32033494718 = 2 ⋅16016747359.

It is a cyclic number.

It is not a de Polignac number, because 81749433023 - 2² = 81749433019 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 (81749433053) 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, 333986 + ... + 524447.

It is an arithmetic number, because the mean of its divisors is an integer number (20437596672).

Almost surely, 2^81749433023 is an apocalyptic number.

81749433023 is a deficient number, since it is larger than the sum of its proper divisors (953665).

81749433023 is an equidigital number, since it uses as much as digits as its factorization.

81749433023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 953664.

The product of its (nonzero) digits is 435456, while the sum is 44.

The spelling of 81749433023 in words is "eighty-one billion, seven hundred forty-nine million, four hundred thirty-three thousand, twenty-three".