20552161 has 4 divisors (see below), whose sum is σ = 23488192. Its totient is φ = 17616132.

The previous prime is 20552149. The next prime is 20552171. The reversal of 20552161 is 16125502.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16125502 = 2 ⋅8062751.

It is a cyclic number.

It is not a de Polignac number, because 20552161 - 2¹³ = 20543969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20552171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1468005 + ... + 1468018.

It is an arithmetic number, because the mean of its divisors is an integer number (5872048).

Almost surely, 2^20552161 is an apocalyptic number.

It is an amenable number.

20552161 is a deficient number, since it is larger than the sum of its proper divisors (2936031).

20552161 is an equidigital number, since it uses as much as digits as its factorization.

20552161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2936030.

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 20552161 is about 4533.4491284231. The cubic root of 20552161 is about 273.9171122290.

Adding to 20552161 its reverse (16125502), we get a palindrome (36677663).

The spelling of 20552161 in words is "twenty million, five hundred fifty-two thousand, one hundred sixty-one".