81803939 has 16 divisors (see below), whose sum is σ = 98522112. Its totient is φ = 66404448.

The previous prime is 81803927. The next prime is 81803951. The reversal of 81803939 is 93930818.

It is an interprime number because it is at equal distance from previous prime (81803927) and next prime (81803951).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81803939 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81803896 and 81803905.

It is not an unprimeable number, because it can be changed into a prime (81803959) 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, 14117 + ... + 19049.

It is an arithmetic number, because the mean of its divisors is an integer number (6157632).

Almost surely, 2^81803939 is an apocalyptic number.

81803939 is a deficient number, since it is larger than the sum of its proper divisors (16718173).

81803939 is a wasteful number, since it uses less digits than its factorization.

81803939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5066.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 81803939 is about 9044.5530016690. The cubic root of 81803939 is about 434.1016188388.

The spelling of 81803939 in words is "eighty-one million, eight hundred three thousand, nine hundred thirty-nine".