81031745081 has 4 divisors (see below), whose sum is σ = 92607708672. Its totient is φ = 69455781492.

The previous prime is 81031745071. The next prime is 81031745089. The reversal of 81031745081 is 18054713018.

It is a happy number.

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 not a de Polignac number, because 81031745081 - 2¹⁸ = 81031482937 is a prime.

It is a super-2 number, since 2×81031745081² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81031745089) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5787981785 + ... + 5787981798.

It is an arithmetic number, because the mean of its divisors is an integer number (23151927168).

Almost surely, 2^81031745081 is an apocalyptic number.

It is an amenable number.

81031745081 is a deficient number, since it is larger than the sum of its proper divisors (11575963591).

81031745081 is a wasteful number, since it uses less digits than its factorization.

81031745081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11575963590.

The product of its (nonzero) digits is 26880, while the sum is 38.

The spelling of 81031745081 in words is "eighty-one billion, thirty-one million, seven hundred forty-five thousand, eighty-one".