81018471007 has 4 divisors (see below), whose sum is σ = 85282601080. Its totient is φ = 76754340936.

The previous prime is 81018470971. The next prime is 81018471013. The reversal of 81018471007 is 70017481018.

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 81018471007 - 2³⁵ = 46658732639 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 (81018471047) 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, 2132065008 + ... + 2132065045.

It is an arithmetic number, because the mean of its divisors is an integer number (21320650270).

Almost surely, 2^81018471007 is an apocalyptic number.

81018471007 is a deficient number, since it is larger than the sum of its proper divisors (4264130073).

81018471007 is a wasteful number, since it uses less digits than its factorization.

81018471007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4264130072.

The product of its (nonzero) digits is 12544, while the sum is 37.

The spelling of 81018471007 in words is "eighty-one billion, eighteen million, four hundred seventy-one thousand, seven".