20045521 has 2 divisors, whose sum is σ = 20045522. Its totient is φ = 20045520.

The previous prime is 20045507. The next prime is 20045537. The reversal of 20045521 is 12554002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15681600 + 4363921 = 3960^2 + 2089^2 .

It is a cyclic number.

It is not a de Polignac number, because 20045521 - 2¹⁷ = 19914449 is a prime.

It is a super-2 number, since 2×20045521² = 803645824322882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20045591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10022760 + 10022761.

It is an arithmetic number, because the mean of its divisors is an integer number (10022761).

Almost surely, 2^20045521 is an apocalyptic number.

It is an amenable number.

20045521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20045521 is an equidigital number, since it uses as much as digits as its factorization.

20045521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 20045521 is about 4477.2224648771. Note that the first 3 decimals coincide. The cubic root of 20045521 is about 271.6475439553.

Adding to 20045521 its reverse (12554002), we get a palindrome (32599523).

The spelling of 20045521 in words is "twenty million, forty-five thousand, five hundred twenty-one".