20805685178668 has 24 divisors (see below), whose sum is σ = 39271695331568. Its totient is φ = 9587689816896.

The previous prime is 20805685178653. The next prime is 20805685178671. The reversal of 20805685178668 is 86687158650802.

It is a junction number, because it is equal to n+sod(n) for n = 20805685178597 and 20805685178606.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 311093571 + ... + 311160442.

Almost surely, 2^{20805685178668} is an apocalyptic number.

It is an amenable number.

20805685178668 is a deficient number, since it is larger than the sum of its proper divisors (18466010152900).

20805685178668 is a wasteful number, since it uses less digits than its factorization.

20805685178668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 622254673 (or 622254671 counting only the distinct ones).

The product of its (nonzero) digits is 309657600, while the sum is 70.

The spelling of 20805685178668 in words is "twenty trillion, eight hundred five billion, six hundred eighty-five million, one hundred seventy-eight thousand, six hundred sixty-eight".