81156764265 has 16 divisors (see below), whose sum is σ = 130710765696. Its totient is φ = 42996960000.

The previous prime is 81156764261. The next prime is 81156764291. The reversal of 81156764265 is 56246765118.

It is a happy number.

It is not a de Polignac number, because 81156764265 - 2² = 81156764261 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81156764261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17913136 + ... + 17917665.

It is an arithmetic number, because the mean of its divisors is an integer number (8169422856).

Almost surely, 2^81156764265 is an apocalyptic number.

It is an amenable number.

81156764265 is a deficient number, since it is larger than the sum of its proper divisors (49554001431).

81156764265 is a wasteful number, since it uses less digits than its factorization.

81156764265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35830960.

The product of its digits is 2419200, while the sum is 51.

The spelling of 81156764265 in words is "eighty-one billion, one hundred fifty-six million, seven hundred sixty-four thousand, two hundred sixty-five".