20010521 has 4 divisors (see below), whose sum is σ = 20388132. Its totient is φ = 19632912.

The previous prime is 20010517. The next prime is 20010533. The reversal of 20010521 is 12501002.

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 6431296 + 13579225 = 2536^2 + 3685^2 .

It is a cyclic number.

It is not a de Polignac number, because 20010521 - 2² = 20010517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20010721) 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, 188726 + ... + 188831.

It is an arithmetic number, because the mean of its divisors is an integer number (5097033).

Almost surely, 2^20010521 is an apocalyptic number.

It is an amenable number.

20010521 is a deficient number, since it is larger than the sum of its proper divisors (377611).

20010521 is an equidigital number, since it uses as much as digits as its factorization.

20010521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 377610.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 20010521 is about 4473.3120839038. The cubic root of 20010521 is about 271.4893506286.

Adding to 20010521 its reverse (12501002), we get a palindrome (32511523).

The spelling of 20010521 in words is "twenty million, ten thousand, five hundred twenty-one".