81931741 has 4 divisors (see below), whose sum is σ = 82066012. Its totient is φ = 81797472.

The previous prime is 81931711. The next prime is 81931753. The reversal of 81931741 is 14713918.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 119716 + 81812025 = 346^2 + 9045^2 .

It is a cyclic number.

It is not a de Polignac number, because 81931741 - 2⁹ = 81931229 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81931697 and 81931706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81931711) 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, 66216 + ... + 67441.

It is an arithmetic number, because the mean of its divisors is an integer number (20516503).

Almost surely, 2^81931741 is an apocalyptic number.

It is an amenable number.

81931741 is a deficient number, since it is larger than the sum of its proper divisors (134271).

81931741 is a wasteful number, since it uses less digits than its factorization.

81931741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134270.

The product of its digits is 6048, while the sum is 34.

The square root of 81931741 is about 9051.6153806931. The cubic root of 81931741 is about 434.3275663471.

The spelling of 81931741 in words is "eighty-one million, nine hundred thirty-one thousand, seven hundred forty-one".