20125643136161 has 4 divisors (see below), whose sum is σ = 20125671519300. Its totient is φ = 20125614753024.

The previous prime is 20125643136089. The next prime is 20125643136233. The reversal of 20125643136161 is 16163134652102.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (20125643136089) and next prime (20125643136233).

It can be written as a sum of positive squares in 2 ways, for example, as 4479385999936 + 15646257136225 = 2116456^2 + 3955535^2 .

It is a cyclic number.

It is not a de Polignac number, because 20125643136161 - 2³⁰ = 20124569394337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20125643136961) 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, 13099976 + ... + 14555433.

It is an arithmetic number, because the mean of its divisors is an integer number (5031417879825).

Almost surely, 2^{20125643136161} is an apocalyptic number.

It is an amenable number.

20125643136161 is a deficient number, since it is larger than the sum of its proper divisors (28383139).

20125643136161 is an equidigital number, since it uses as much as digits as its factorization.

20125643136161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28383138.

The product of its (nonzero) digits is 155520, while the sum is 41.

Adding to 20125643136161 its reverse (16163134652102), we get a palindrome (36288777788263).

The spelling of 20125643136161 in words is "twenty trillion, one hundred twenty-five billion, six hundred forty-three million, one hundred thirty-six thousand, one hundred sixty-one".