20477312161 has 4 divisors (see below), whose sum is σ = 20530778112. Its totient is φ = 20423846212.

The previous prime is 20477312147. The next prime is 20477312173. The reversal of 20477312161 is 16121377402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20477312161 - 2⁵ = 20477312129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20477312131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26732401 + ... + 26733166.

It is an arithmetic number, because the mean of its divisors is an integer number (5132694528).

Almost surely, 2^20477312161 is an apocalyptic number.

It is an amenable number.

20477312161 is a deficient number, since it is larger than the sum of its proper divisors (53465951).

20477312161 is an equidigital number, since it uses as much as digits as its factorization.

20477312161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53465950.

The product of its (nonzero) digits is 14112, while the sum is 34.

Adding to 20477312161 its reverse (16121377402), we get a palindrome (36598689563).

The spelling of 20477312161 in words is "twenty billion, four hundred seventy-seven million, three hundred twelve thousand, one hundred sixty-one".