81471722961 has 16 divisors (see below), whose sum is σ = 114417561600. Its totient is φ = 51423747408.

The previous prime is 81471722939. The next prime is 81471723041. The reversal of 81471722961 is 16922717418.

It is not a de Polignac number, because 81471722961 - 2¹⁵ = 81471690193 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81471722961.

It is not an unprimeable number, because it can be changed into a prime (81471722921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 353121 + ... + 536318.

It is an arithmetic number, because the mean of its divisors is an integer number (7151097600).

Almost surely, 2^81471722961 is an apocalyptic number.

It is an amenable number.

81471722961 is a deficient number, since it is larger than the sum of its proper divisors (32945838639).

81471722961 is a wasteful number, since it uses less digits than its factorization.

81471722961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891068.

The product of its digits is 338688, while the sum is 48.

The spelling of 81471722961 in words is "eighty-one billion, four hundred seventy-one million, seven hundred twenty-two thousand, nine hundred sixty-one".