21600121 has 2 divisors, whose sum is σ = 21600122. Its totient is φ = 21600120.

The previous prime is 21600091. The next prime is 21600133. The reversal of 21600121 is 12100612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11289600 + 10310521 = 3360^2 + 3211^2 .

It is a cyclic number.

It is not a de Polignac number, because 21600121 - 2¹³ = 21591929 is a prime.

It is not a weakly prime, because it can be changed into another prime (21600181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10800060 + 10800061.

It is an arithmetic number, because the mean of its divisors is an integer number (10800061).

Almost surely, 2^21600121 is an apocalyptic number.

It is an amenable number.

21600121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21600121 is an equidigital number, since it uses as much as digits as its factorization.

21600121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 21600121 is about 4647.5930329580. The cubic root of 21600121 is about 278.4958500457.

Adding to 21600121 its reverse (12100612), we get a palindrome (33700733).

The spelling of 21600121 in words is "twenty-one million, six hundred thousand, one hundred twenty-one".