21221132369 has 2 divisors, whose sum is σ = 21221132370. Its totient is φ = 21221132368.

The previous prime is 21221132327. The next prime is 21221132371. The reversal of 21221132369 is 96323112212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20880250000 + 340882369 = 144500^2 + 18463^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221132369 is a prime.

It is a super-2 number, since 2×21221132369² (a number of 21 digits) contains 22 as substring.

Together with 21221132371, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21221137369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610566184 + 10610566185.

It is an arithmetic number, because the mean of its divisors is an integer number (10610566185).

Almost surely, 2^21221132369 is an apocalyptic number.

It is an amenable number.

21221132369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221132369 is an equidigital number, since it uses as much as digits as its factorization.

21221132369 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 32.

The spelling of 21221132369 in words is "twenty-one billion, two hundred twenty-one million, one hundred thirty-two thousand, three hundred sixty-nine".