21231205201 has 2 divisors, whose sum is σ = 21231205202. Its totient is φ = 21231205200.

The previous prime is 21231205159. The next prime is 21231205211. The reversal of 21231205201 is 10250213212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12068121025 + 9163084176 = 109855^2 + 95724^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231205201 - 2¹⁵ = 21231172433 is a prime.

It is not a weakly prime, because it can be changed into another prime (21231205211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615602600 + 10615602601.

It is an arithmetic number, because the mean of its divisors is an integer number (10615602601).

Almost surely, 2^21231205201 is an apocalyptic number.

It is an amenable number.

21231205201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231205201 is an equidigital number, since it uses as much as digits as its factorization.

21231205201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 21231205201 its reverse (10250213212), we get a palindrome (31481418413).

The spelling of 21231205201 in words is "twenty-one billion, two hundred thirty-one million, two hundred five thousand, two hundred one".