81007018501 has 4 divisors (see below), whose sum is σ = 81034360992. Its totient is φ = 80979676012.

The previous prime is 81007018481. The next prime is 81007018507. The reversal of 81007018501 is 10581070018.

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 81007018501 - 2⁷ = 81007018373 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 (81007018507) 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, 13666801 + ... + 13672726.

It is an arithmetic number, because the mean of its divisors is an integer number (20258590248).

Almost surely, 2^81007018501 is an apocalyptic number.

It is an amenable number.

81007018501 is a deficient number, since it is larger than the sum of its proper divisors (27342491).

81007018501 is a wasteful number, since it uses less digits than its factorization.

81007018501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27342490.

The product of its (nonzero) digits is 2240, while the sum is 31.

Adding to 81007018501 its reverse (10581070018), we get a palindrome (91588088519).

The spelling of 81007018501 in words is "eighty-one billion, seven million, eighteen thousand, five hundred one".