81023032513 has 4 divisors (see below), whose sum is σ = 81434317140. Its totient is φ = 80611747888.

The previous prime is 81023032507. The next prime is 81023032549. The reversal of 81023032513 is 31523032018.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31523032018 = 2 ⋅15761516009.

It can be written as a sum of positive squares in 2 ways, for example, as 57124346049 + 23898686464 = 239007^2 + 154592^2 .

It is a cyclic number.

It is not a de Polignac number, because 81023032513 - 2⁵ = 81023032481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81023032313) 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, 205642018 + ... + 205642411.

It is an arithmetic number, because the mean of its divisors is an integer number (20358579285).

Almost surely, 2^81023032513 is an apocalyptic number.

It is an amenable number.

81023032513 is a deficient number, since it is larger than the sum of its proper divisors (411284627).

81023032513 is a wasteful number, since it uses less digits than its factorization.

81023032513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 411284626.

The product of its (nonzero) digits is 4320, while the sum is 28.

The spelling of 81023032513 in words is "eighty-one billion, twenty-three million, thirty-two thousand, five hundred thirteen".