81793785 has 16 divisors (see below), whose sum is σ = 131071680. Its totient is φ = 43556160.

The previous prime is 81793781. The next prime is 81793793. The reversal of 81793785 is 58739718.

It is not a de Polignac number, because 81793785 - 2² = 81793781 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81793781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6790 + ... + 14480.

It is an arithmetic number, because the mean of its divisors is an integer number (8191980).

Almost surely, 2^81793785 is an apocalyptic number.

It is an amenable number.

81793785 is a deficient number, since it is larger than the sum of its proper divisors (49277895).

81793785 is a wasteful number, since it uses less digits than its factorization.

81793785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8408.

The product of its digits is 423360, while the sum is 48.

The square root of 81793785 is about 9043.9916519201. The cubic root of 81793785 is about 434.0836569889.

The spelling of 81793785 in words is "eighty-one million, seven hundred ninety-three thousand, seven hundred eighty-five".