71839787681 has 8 divisors (see below), whose sum is σ = 72213621480. Its totient is φ = 71466046848.

The previous prime is 71839787659. The next prime is 71839787699. The reversal of 71839787681 is 18678793817.

It can be written as a sum of positive squares in 4 ways, for example, as 9297780625 + 62542007056 = 96425^2 + 250084^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71839787681 is a prime.

It is a super-2 number, since 2×71839787681² (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 (71839787651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1965485 + ... + 2001701.

It is an arithmetic number, because the mean of its divisors is an integer number (9026702685).

Almost surely, 2^71839787681 is an apocalyptic number.

It is an amenable number.

71839787681 is a deficient number, since it is larger than the sum of its proper divisors (373833799).

71839787681 is a wasteful number, since it uses less digits than its factorization.

71839787681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46483.

The product of its digits is 28449792, while the sum is 65.

The spelling of 71839787681 in words is "seventy-one billion, eight hundred thirty-nine million, seven hundred eighty-seven thousand, six hundred eighty-one".