81683929 has 4 divisors (see below), whose sum is σ = 86488884. Its totient is φ = 76878976.

The previous prime is 81683911. The next prime is 81683939. The reversal of 81683929 is 92938618.

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 57032704 + 24651225 = 7552^2 + 4965^2 .

It is a cyclic number.

It is not a de Polignac number, because 81683929 - 2⁵ = 81683897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81683939) 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, 2402452 + ... + 2402485.

It is an arithmetic number, because the mean of its divisors is an integer number (21622221).

Almost surely, 2^81683929 is an apocalyptic number.

It is an amenable number.

81683929 is a deficient number, since it is larger than the sum of its proper divisors (4804955).

81683929 is a wasteful number, since it uses less digits than its factorization.

81683929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4804954.

The product of its digits is 186624, while the sum is 46.

The square root of 81683929 is about 9037.9161868209. The cubic root of 81683929 is about 433.8892328475.

It can be divided in two parts, 81 and 683929, that multiplied together give a square (55398249 = 7443²).

The spelling of 81683929 in words is "eighty-one million, six hundred eighty-three thousand, nine hundred twenty-nine".