81385204 has 6 divisors (see below), whose sum is σ = 142424114. Its totient is φ = 40692600.

The previous prime is 81385193. The next prime is 81385253. The reversal of 81385204 is 40258318.

It can be written as a sum of positive squares in only one way, i.e., 41088100 + 40297104 = 6410^2 + 6348^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10173147 + ... + 10173154.

Almost surely, 2^81385204 is an apocalyptic number.

It is an amenable number.

81385204 is a deficient number, since it is larger than the sum of its proper divisors (61038910).

81385204 is a wasteful number, since it uses less digits than its factorization.

81385204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20346305 (or 20346303 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 81385204 is about 9021.3748397902. The cubic root of 81385204 is about 433.3596636203.

The spelling of 81385204 in words is "eighty-one million, three hundred eighty-five thousand, two hundred four".