20013121 has 2 divisors, whose sum is σ = 20013122. Its totient is φ = 20013120.

The previous prime is 20013109. The next prime is 20013127. The reversal of 20013121 is 12131002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12173121 + 7840000 = 3489^2 + 2800^2 .

It is a cyclic number.

It is not a de Polignac number, because 20013121 - 2⁹ = 20012609 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20013098 and 20013107.

It is not a weakly prime, because it can be changed into another prime (20013127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10006560 + 10006561.

It is an arithmetic number, because the mean of its divisors is an integer number (10006561).

Almost surely, 2^20013121 is an apocalyptic number.

It is an amenable number.

20013121 is a deficient number, since it is larger than the sum of its proper divisors (1).

20013121 is an equidigital number, since it uses as much as digits as its factorization.

20013121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 20013121 is about 4473.6026868733. The cubic root of 20013121 is about 271.5011084725.

Adding to 20013121 its reverse (12131002), we get a palindrome (32144123).

The spelling of 20013121 in words is "twenty million, thirteen thousand, one hundred twenty-one".