20511671205205 has 16 divisors (see below), whose sum is σ = 24793955956224. Its totient is φ = 16289692021440.

The previous prime is 20511671205173. The next prime is 20511671205251. The reversal of 20511671205205 is 50250217611502.

It is not a de Polignac number, because 20511671205205 - 2⁵ = 20511671205173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19619109 + ... + 20638138.

It is an arithmetic number, because the mean of its divisors is an integer number (1549622247264).

Almost surely, 2^{20511671205205} is an apocalyptic number.

It is an amenable number.

20511671205205 is a deficient number, since it is larger than the sum of its proper divisors (4282284751019).

20511671205205 is a wasteful number, since it uses less digits than its factorization.

20511671205205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40257996.

The product of its (nonzero) digits is 42000, while the sum is 37.

Adding to 20511671205205 its reverse (50250217611502), we get a palindrome (70761888816707).

The spelling of 20511671205205 in words is "twenty trillion, five hundred eleven billion, six hundred seventy-one million, two hundred five thousand, two hundred five".