21201312361 has 2 divisors, whose sum is σ = 21201312362. Its totient is φ = 21201312360.

The previous prime is 21201312311. The next prime is 21201312367. The reversal of 21201312361 is 16321310212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18004540761 + 3196771600 = 134181^2 + 56540^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201312361 - 2¹¹ = 21201310313 is a prime.

It is not a weakly prime, because it can be changed into another prime (21201312367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600656180 + 10600656181.

It is an arithmetic number, because the mean of its divisors is an integer number (10600656181).

Almost surely, 2^21201312361 is an apocalyptic number.

It is an amenable number.

21201312361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201312361 is an equidigital number, since it uses as much as digits as its factorization.

21201312361 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 22.

Adding to 21201312361 its reverse (16321310212), we get a palindrome (37522622573).

The spelling of 21201312361 in words is "twenty-one billion, two hundred one million, three hundred twelve thousand, three hundred sixty-one".