20090521 has 4 divisors (see below), whose sum is σ = 21916944. Its totient is φ = 18264100.

The previous prime is 20090491. The next prime is 20090527. The reversal of 20090521 is 12509002.

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.

It is a cyclic number.

It is not a de Polignac number, because 20090521 - 2⁷ = 20090393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20090527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 913195 + ... + 913216.

It is an arithmetic number, because the mean of its divisors is an integer number (5479236).

Almost surely, 2^20090521 is an apocalyptic number.

It is an amenable number.

20090521 is a deficient number, since it is larger than the sum of its proper divisors (1826423).

20090521 is a wasteful number, since it uses less digits than its factorization.

20090521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1826422.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 20090521 is about 4482.2450847762. The cubic root of 20090521 is about 271.8506650346.

Adding to 20090521 its reverse (12509002), we get a palindrome (32599523).

The spelling of 20090521 in words is "twenty million, ninety thousand, five hundred twenty-one".