81609976371 has 32 divisors (see below), whose sum is σ = 135799792128. Its totient is φ = 42352151040.

The previous prime is 81609976367. The next prime is 81609976421. The reversal of 81609976371 is 17367990618.

It is not a de Polignac number, because 81609976371 - 2² = 81609976367 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81609976321) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 53131 + ... + 407483.

It is an arithmetic number, because the mean of its divisors is an integer number (4243743504).

Almost surely, 2^81609976371 is an apocalyptic number.

81609976371 is a deficient number, since it is larger than the sum of its proper divisors (54189815757).

81609976371 is a wasteful number, since it uses less digits than its factorization.

81609976371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355371.

The product of its (nonzero) digits is 3429216, while the sum is 57.

The spelling of 81609976371 in words is "eighty-one billion, six hundred nine million, nine hundred seventy-six thousand, three hundred seventy-one".