20528161 has 4 divisors (see below), whose sum is σ = 20547972. Its totient is φ = 20508352.

The previous prime is 20528087. The next prime is 20528171. The reversal of 20528161 is 16182502.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11189025 + 9339136 = 3345^2 + 3056^2 .

It is a cyclic number.

It is not a de Polignac number, because 20528161 - 2⁷ = 20528033 is a prime.

It is a super-3 number, since 3×20528161³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20528171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8260 + ... + 10453.

It is an arithmetic number, because the mean of its divisors is an integer number (5136993).

Almost surely, 2^20528161 is an apocalyptic number.

It is an amenable number.

20528161 is a deficient number, since it is larger than the sum of its proper divisors (19811).

20528161 is a wasteful number, since it uses less digits than its factorization.

20528161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19810.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 20528161 is about 4530.8013639973. The cubic root of 20528161 is about 273.8104475120.

The spelling of 20528161 in words is "twenty million, five hundred twenty-eight thousand, one hundred sixty-one".