81735261737 has 4 divisors (see below), whose sum is σ = 81912562116. Its totient is φ = 81557961360.

The previous prime is 81735261691. The next prime is 81735261749. The reversal of 81735261737 is 73716253718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73716253718 = 2 ⋅36858126859.

It can be written as a sum of positive squares in 2 ways, for example, as 50186752576 + 31548509161 = 224024^2 + 177619^2 .

It is a cyclic number.

It is not a de Polignac number, because 81735261737 - 2⁸ = 81735261481 is a prime.

It is a super-2 number, since 2×81735261737² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81735261037) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 88649498 + ... + 88650419.

It is an arithmetic number, because the mean of its divisors is an integer number (20478140529).

Almost surely, 2^81735261737 is an apocalyptic number.

It is an amenable number.

81735261737 is a deficient number, since it is larger than the sum of its proper divisors (177300379).

81735261737 is a wasteful number, since it uses less digits than its factorization.

81735261737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177300378.

The product of its digits is 1481760, while the sum is 50.

The spelling of 81735261737 in words is "eighty-one billion, seven hundred thirty-five million, two hundred sixty-one thousand, seven hundred thirty-seven".