81434345761 has 16 divisors (see below), whose sum is σ = 87273838800. Its totient is φ = 75713026048.

The previous prime is 81434345747. The next prime is 81434345803. The reversal of 81434345761 is 16754343418.

It can be written as a sum of positive squares in 8 ways, for example, as 1322704161 + 80111641600 = 36369^2 + 283040^2 .

It is a cyclic number.

It is not a de Polignac number, because 81434345761 - 2²⁹ = 80897474849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81434345711) 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, 1653651 + ... + 1702183.

It is an arithmetic number, because the mean of its divisors is an integer number (5454614925).

Almost surely, 2^81434345761 is an apocalyptic number.

It is an amenable number.

81434345761 is a deficient number, since it is larger than the sum of its proper divisors (5839493039).

81434345761 is a wasteful number, since it uses less digits than its factorization.

81434345761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49748.

The product of its digits is 967680, while the sum is 46.

The spelling of 81434345761 in words is "eighty-one billion, four hundred thirty-four million, three hundred forty-five thousand, seven hundred sixty-one".