20565205406 has 16 divisors (see below), whose sum is σ = 31916127600. Its totient is φ = 9926598528.

The previous prime is 20565205391. The next prime is 20565205411. The reversal of 20565205406 is 60450256502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 458405 + ... + 501263.

It is an arithmetic number, because the mean of its divisors is an integer number (1994757975).

Almost surely, 2^20565205406 is an apocalyptic number.

20565205406 is a deficient number, since it is larger than the sum of its proper divisors (11350922194).

20565205406 is a wasteful number, since it uses less digits than its factorization.

20565205406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51163.

The product of its (nonzero) digits is 72000, while the sum is 35.

The spelling of 20565205406 in words is "twenty billion, five hundred sixty-five million, two hundred five thousand, four hundred six".