81359747 has 12 divisors (see below), whose sum is σ = 94859856. Its totient is φ = 69577200.

The previous prime is 81359743. The next prime is 81359753. The reversal of 81359747 is 74795318.

It is not a de Polignac number, because 81359747 - 2² = 81359743 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81359698 and 81359707.

It is not an unprimeable number, because it can be changed into a prime (81359743) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22997 + ... + 26297.

It is an arithmetic number, because the mean of its divisors is an integer number (7904988).

Almost surely, 2^81359747 is an apocalyptic number.

81359747 is a deficient number, since it is larger than the sum of its proper divisors (13500109).

81359747 is a wasteful number, since it uses less digits than its factorization.

81359747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3818 (or 3811 counting only the distinct ones).

The product of its digits is 211680, while the sum is 44.

The square root of 81359747 is about 9019.9638025881. The cubic root of 81359747 is about 433.3144744587.

The spelling of 81359747 in words is "eighty-one million, three hundred fifty-nine thousand, seven hundred forty-seven".