20529561 has 32 divisors (see below), whose sum is σ = 31102848. Its totient is φ = 11957760.

The previous prime is 20529539. The next prime is 20529569. The reversal of 20529561 is 16592502.

It is a happy number.

It is not a de Polignac number, because 20529561 - 2⁵ = 20529529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20529569) 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 31 ways as a sum of consecutive naturals, for example, 58990 + ... + 59336.

It is an arithmetic number, because the mean of its divisors is an integer number (971964).

Almost surely, 2^20529561 is an apocalyptic number.

It is an amenable number.

20529561 is a deficient number, since it is larger than the sum of its proper divisors (10573287).

20529561 is a wasteful number, since it uses less digits than its factorization.

20529561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441.

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 20529561 is about 4530.9558594186. The cubic root of 20529561 is about 273.8166719032.

The spelling of 20529561 in words is "twenty million, five hundred twenty-nine thousand, five hundred sixty-one".