81687209804 has 12 divisors (see below), whose sum is σ = 147563992128. Its totient is φ = 39526069200.

The previous prime is 81687209753. The next prime is 81687209819. The reversal of 81687209804 is 40890278618.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 329383787 + ... + 329384034.

It is an arithmetic number, because the mean of its divisors is an integer number (12296999344).

Almost surely, 2^81687209804 is an apocalyptic number.

It is an amenable number.

81687209804 is a deficient number, since it is larger than the sum of its proper divisors (65876782324).

81687209804 is a wasteful number, since it uses less digits than its factorization.

81687209804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658767856 (or 658767854 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 53.

The spelling of 81687209804 in words is "eighty-one billion, six hundred eighty-seven million, two hundred nine thousand, eight hundred four".