20393521 has 2 divisors, whose sum is σ = 20393522. Its totient is φ = 20393520.

The previous prime is 20393509. The next prime is 20393579. The reversal of 20393521 is 12539302.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18533025 + 1860496 = 4305^2 + 1364^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20393521 is a prime.

It is not a weakly prime, because it can be changed into another prime (20393221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10196760 + 10196761.

It is an arithmetic number, because the mean of its divisors is an integer number (10196761).

Almost surely, 2^20393521 is an apocalyptic number.

It is an amenable number.

20393521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20393521 is an equidigital number, since it uses as much as digits as its factorization.

20393521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1620, while the sum is 25.

The square root of 20393521 is about 4515.9186219417. The cubic root of 20393521 is about 273.2105117762.

The spelling of 20393521 in words is "twenty million, three hundred ninety-three thousand, five hundred twenty-one".