21601121 has 2 divisors, whose sum is σ = 21601122. Its totient is φ = 21601120.

The previous prime is 21601061. The next prime is 21601171. The reversal of 21601121 is 12110612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16516096 + 5085025 = 4064^2 + 2255^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21601121 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21601096 and 21601105.

It is not a weakly prime, because it can be changed into another prime (21601171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10800560 + 10800561.

It is an arithmetic number, because the mean of its divisors is an integer number (10800561).

Almost surely, 2^21601121 is an apocalyptic number.

It is an amenable number.

21601121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21601121 is an equidigital number, since it uses as much as digits as its factorization.

21601121 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 14.

The square root of 21601121 is about 4647.7006142823. The cubic root of 21601121 is about 278.5001477307.

Adding to 21601121 its reverse (12110612), we get a palindrome (33711733).

The spelling of 21601121 in words is "twenty-one million, six hundred one thousand, one hundred twenty-one".