81807643701 has 36 divisors (see below), whose sum is σ = 137581692300. Its totient is φ = 46705534848.

The previous prime is 81807643681. The next prime is 81807643717. The reversal of 81807643701 is 10734670818.

It can be written as a sum of positive squares in 2 ways, for example, as 2550755025 + 79256888676 = 50505^2 + 281526^2 .

It is not a de Polignac number, because 81807643701 - 2⁶ = 81807643637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81807642701) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 415735 + ... + 580043.

It is an arithmetic number, because the mean of its divisors is an integer number (3821713675).

Almost surely, 2^81807643701 is an apocalyptic number.

It is an amenable number.

81807643701 is a deficient number, since it is larger than the sum of its proper divisors (55774048599).

81807643701 is a wasteful number, since it uses less digits than its factorization.

81807643701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165458 (or 165448 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The spelling of 81807643701 in words is "eighty-one billion, eight hundred seven million, six hundred forty-three thousand, seven hundred one".