20686616402478 has 64 divisors (see below), whose sum is σ = 44714268282432. Its totient is φ = 6342487557120.

The previous prime is 20686616402467. The next prime is 20686616402509. The reversal of 20686616402478 is 87420461668602.

It is a happy number.

It is a Smith number, since the sum of its digits (60) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

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, 68134488 + ... + 68437428.

It is an arithmetic number, because the mean of its divisors is an integer number (698660441913).

Almost surely, 2^{20686616402478} is an apocalyptic number.

20686616402478 is an abundant number, since it is smaller than the sum of its proper divisors (24027651879954).

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

20686616402478 is a wasteful number, since it uses less digits than its factorization.

20686616402478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306069.

The product of its (nonzero) digits is 37158912, while the sum is 60.

The spelling of 20686616402478 in words is "twenty trillion, six hundred eighty-six billion, six hundred sixteen million, four hundred two thousand, four hundred seventy-eight".