21246189121 has 2 divisors, whose sum is σ = 21246189122. Its totient is φ = 21246189120.

The previous prime is 21246189043. The next prime is 21246189227. The reversal of 21246189121 is 12198164212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12422217025 + 8823972096 = 111455^2 + 93936^2 .

It is a cyclic number.

It is not a de Polignac number, because 21246189121 - 2¹¹ = 21246187073 is a prime.

It is not a weakly prime, because it can be changed into another prime (21246189721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10623094560 + 10623094561.

It is an arithmetic number, because the mean of its divisors is an integer number (10623094561).

Almost surely, 2^21246189121 is an apocalyptic number.

It is an amenable number.

21246189121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21246189121 is an equidigital number, since it uses as much as digits as its factorization.

21246189121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 37.

The spelling of 21246189121 in words is "twenty-one billion, two hundred forty-six million, one hundred eighty-nine thousand, one hundred twenty-one".