21121201 has 2 divisors, whose sum is σ = 21121202. Its totient is φ = 21121200.

The previous prime is 21121187. The next prime is 21121207. The reversal of 21121201 is 10212112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20711601 + 409600 = 4551^2 + 640^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121201 - 2⁹ = 21120689 is a prime.

It is a super-2 number, since 2×21121201² = 892210263364802, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560600 + 10560601.

It is an arithmetic number, because the mean of its divisors is an integer number (10560601).

Almost surely, 2^21121201 is an apocalyptic number.

It is an amenable number.

21121201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121201 is an equidigital number, since it uses as much as digits as its factorization.

21121201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 21121201 is about 4595.7807824134. The cubic root of 21121201 is about 276.4221686329.

Adding to 21121201 its reverse (10212112), we get a palindrome (31333313).

It can be divided in two parts, 211 and 21201, that added together give a palindrome (21412).

The spelling of 21121201 in words is "twenty-one million, one hundred twenty-one thousand, two hundred one".