21121241 has 2 divisors, whose sum is σ = 21121242. Its totient is φ = 21121240.

The previous prime is 21121237. The next prime is 21121249. The reversal of 21121241 is 14212112.

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., 12145225 + 8976016 = 3485^2 + 2996^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121241 - 2² = 21121237 is a prime.

It is a super-2 number, since 2×21121241² = 892213642760162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560620 + 10560621.

It is an arithmetic number, because the mean of its divisors is an integer number (10560621).

Almost surely, 2^21121241 is an apocalyptic number.

It is an amenable number.

21121241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121241 is an equidigital number, since it uses as much as digits as its factorization.

21121241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32, while the sum is 14.

The square root of 21121241 is about 4595.7851342290. The cubic root of 21121241 is about 276.4223431318.

Adding to 21121241 its reverse (14212112), we get a palindrome (35333353).

The spelling of 21121241 in words is "twenty-one million, one hundred twenty-one thousand, two hundred forty-one".