81665120204 has 6 divisors (see below), whose sum is σ = 142913960364. Its totient is φ = 40832560100.

The previous prime is 81665120189. The next prime is 81665120233. The reversal of 81665120204 is 40202156618.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10208140022 + ... + 10208140029.

It is an arithmetic number, because the mean of its divisors is an integer number (23818993394).

Almost surely, 2^81665120204 is an apocalyptic number.

It is an amenable number.

81665120204 is a deficient number, since it is larger than the sum of its proper divisors (61248840160).

81665120204 is a wasteful number, since it uses less digits than its factorization.

81665120204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20416280055 (or 20416280053 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 35.

The spelling of 81665120204 in words is "eighty-one billion, six hundred sixty-five million, one hundred twenty thousand, two hundred four".