81743845 has 8 divisors (see below), whose sum is σ = 99064440. Its totient is φ = 64747200.

The previous prime is 81743821. The next prime is 81743897. The reversal of 81743845 is 54834718.

It can be written as a sum of positive squares in 4 ways, for example, as 36397089 + 45346756 = 6033^2 + 6734^2 .

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

It is not a de Polignac number, because 81743845 - 2¹³ = 81735653 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81743798 and 81743807.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80430 + ... + 81439.

It is an arithmetic number, because the mean of its divisors is an integer number (12383055).

Almost surely, 2^81743845 is an apocalyptic number.

It is an amenable number.

81743845 is a deficient number, since it is larger than the sum of its proper divisors (17320595).

81743845 is a wasteful number, since it uses less digits than its factorization.

81743845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161975.

The product of its digits is 107520, while the sum is 40.

The square root of 81743845 is about 9041.2302813279. The cubic root of 81743845 is about 433.9952943206.

The spelling of 81743845 in words is "eighty-one million, seven hundred forty-three thousand, eight hundred forty-five".