20720856687408 has 60 divisors (see below), whose sum is σ = 60510907582320. Its totient is φ = 6606649957248.

The previous prime is 20720856687389. The next prime is 20720856687437. The reversal of 20720856687408 is 80478665802702.

20720856687408 is a `hidden beast` number, since 2 + 0 + 7 + 20 + 8 + 566 + 8 + 7 + 40 + 8 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3128145343 + ... + 3128151966.

It is an arithmetic number, because the mean of its divisors is an integer number (1008515126372).

Almost surely, 2^{20720856687408} is an apocalyptic number.

It is an amenable number.

20720856687408 is an abundant number, since it is smaller than the sum of its proper divisors (39790050894912).

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

20720856687408 is a wasteful number, since it uses less digits than its factorization.

20720856687408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6256297346 (or 6256297337 counting only the distinct ones).

The product of its (nonzero) digits is 72253440, while the sum is 63.

The spelling of 20720856687408 in words is "twenty trillion, seven hundred twenty billion, eight hundred fifty-six million, six hundred eighty-seven thousand, four hundred eight".