81209804215 has 16 divisors (see below), whose sum is σ = 97734838176. Its totient is φ = 64779264000.

The previous prime is 81209804191. The next prime is 81209804267. The reversal of 81209804215 is 51240890218.

It is not a de Polignac number, because 81209804215 - 2¹⁹ = 81209279927 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5950039 + ... + 5963671.

It is an arithmetic number, because the mean of its divisors is an integer number (6108427386).

Almost surely, 2^81209804215 is an apocalyptic number.

81209804215 is a deficient number, since it is larger than the sum of its proper divisors (16525033961).

81209804215 is a wasteful number, since it uses less digits than its factorization.

81209804215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17010.

The product of its (nonzero) digits is 46080, while the sum is 40.

The spelling of 81209804215 in words is "eighty-one billion, two hundred nine million, eight hundred four thousand, two hundred fifteen".