81808029 has 16 divisors (see below), whose sum is σ = 128327040. Its totient is φ = 51330240.

The previous prime is 81808021. The next prime is 81808031. The reversal of 81808029 is 92080818.

It is not a de Polignac number, because 81808029 - 2³ = 81808021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81807984 and 81808002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81808021) 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, 88657 + ... + 89574.

It is an arithmetic number, because the mean of its divisors is an integer number (8020440).

Almost surely, 2^81808029 is an apocalyptic number.

It is an amenable number.

81808029 is a deficient number, since it is larger than the sum of its proper divisors (46519011).

81808029 is a wasteful number, since it uses less digits than its factorization.

81808029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178257 (or 178251 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 81808029 is about 9044.7791017802. The cubic root of 81808029 is about 434.1088533968.

The spelling of 81808029 in words is "eighty-one million, eight hundred eight thousand, twenty-nine".