21321612241 has 2 divisors, whose sum is σ = 21321612242. Its totient is φ = 21321612240.

The previous prime is 21321612239. The next prime is 21321612317. The reversal of 21321612241 is 14221612312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20543202241 + 778410000 = 143329^2 + 27900^2 .

It is a cyclic number.

It is not a de Polignac number, because 21321612241 - 2¹ = 21321612239 is a prime.

It is a super-2 number, since 2×21321612241² (a number of 21 digits) contains 22 as substring.

Together with 21321612239, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21321612941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660806120 + 10660806121.

It is an arithmetic number, because the mean of its divisors is an integer number (10660806121).

Almost surely, 2^21321612241 is an apocalyptic number.

It is an amenable number.

21321612241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21321612241 is an equidigital number, since it uses as much as digits as its factorization.

21321612241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 25.

The spelling of 21321612241 in words is "twenty-one billion, three hundred twenty-one million, six hundred twelve thousand, two hundred forty-one".