20320521 has 8 divisors (see below), whose sum is σ = 29178240. Its totient is φ = 12504912.

The previous prime is 20320507. The next prime is 20320537. The reversal of 20320521 is 12502302.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-20320521 is a prime.

It is a super-2 number, since 2×20320521² = 825847147422882, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20320521.

It is not an unprimeable number, because it can be changed into a prime (20320541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 260481 + ... + 260558.

It is an arithmetic number, because the mean of its divisors is an integer number (3647280).

Almost surely, 2^20320521 is an apocalyptic number.

It is an amenable number.

20320521 is a deficient number, since it is larger than the sum of its proper divisors (8857719).

20320521 is a wasteful number, since it uses less digits than its factorization.

20320521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521055.

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 20320521 is about 4507.8288565561. The cubic root of 20320521 is about 272.8841301409.

Adding to 20320521 its reverse (12502302), we get a palindrome (32822823).

The spelling of 20320521 in words is "twenty million, three hundred twenty thousand, five hundred twenty-one".