81209947227 has 16 divisors (see below), whose sum is σ = 111868431360. Its totient is φ = 52348701600.

The previous prime is 81209947211. The next prime is 81209947229. The reversal of 81209947227 is 72274990218.

It is not a de Polignac number, because 81209947227 - 2⁴ = 81209947211 is a prime.

It is a super-2 number, since 2×81209947227² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81209947227.

It is not an unprimeable number, because it can be changed into a prime (81209947229) 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, 263952 + ... + 481757.

It is an arithmetic number, because the mean of its divisors is an integer number (6991776960).

Almost surely, 2^81209947227 is an apocalyptic number.

81209947227 is a deficient number, since it is larger than the sum of its proper divisors (30658484133).

81209947227 is a wasteful number, since it uses less digits than its factorization.

81209947227 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 746914.

The product of its (nonzero) digits is 1016064, while the sum is 51.

The spelling of 81209947227 in words is "eighty-one billion, two hundred nine million, nine hundred forty-seven thousand, two hundred twenty-seven".