20897929856808 has 128 divisors (see below), whose sum is σ = 60403492108800. Its totient is φ = 6689127115008.

The previous prime is 20897929856717. The next prime is 20897929856849. The reversal of 20897929856808 is 80865892979802.

It is a happy number.

20897929856808 is a `hidden beast` number, since 20 + 8 + 9 + 7 + 9 + 29 + 8 + 568 + 0 + 8 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18881791 + ... + 19957902.

It is an arithmetic number, because the mean of its divisors is an integer number (471902282100).

Almost surely, 2^{20897929856808} is an apocalyptic number.

It is an amenable number.

20897929856808 is an abundant number, since it is smaller than the sum of its proper divisors (39505562251992).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20897929856808 is a wasteful number, since it uses less digits than its factorization.

20897929856808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38839808 (or 38839798 counting only the distinct ones).

The product of its (nonzero) digits is 2508226560, while the sum is 81.

The spelling of 20897929856808 in words is "twenty trillion, eight hundred ninety-seven billion, nine hundred twenty-nine million, eight hundred fifty-six thousand, eight hundred eight".