81808036 has 12 divisors (see below), whose sum is σ = 147033628. Its totient is φ = 39798432.

The previous prime is 81808031. The next prime is 81808049. The reversal of 81808036 is 63080818.

It can be written as a sum of positive squares in 2 ways, for example, as 71503936 + 10304100 = 8456^2 + 3210^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81807992 and 81808010.

It is not an unprimeable number, because it can be changed into a prime (81808031) 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, 276231 + ... + 276526.

Almost surely, 2^81808036 is an apocalyptic number.

It is an amenable number.

81808036 is a deficient number, since it is larger than the sum of its proper divisors (65225592).

81808036 is a wasteful number, since it uses less digits than its factorization.

81808036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 552798 (or 552796 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 81808036 is about 9044.7794887438. The cubic root of 81808036 is about 434.1088657785.

The spelling of 81808036 in words is "eighty-one million, eight hundred eight thousand, thirty-six".