20321131261 has 2 divisors, whose sum is σ = 20321131262. Its totient is φ = 20321131260.

The previous prime is 20321131247. The next prime is 20321131297. The reversal of 20321131261 is 16213112302.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10605086361 + 9716044900 = 102981^2 + 98570^2 .

It is a cyclic number.

It is not a de Polignac number, because 20321131261 - 2⁹ = 20321130749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20321131241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10160565630 + 10160565631.

It is an arithmetic number, because the mean of its divisors is an integer number (10160565631).

Almost surely, 2^20321131261 is an apocalyptic number.

It is an amenable number.

20321131261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20321131261 is an equidigital number, since it uses as much as digits as its factorization.

20321131261 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 20321131261 its reverse (16213112302), we get a palindrome (36534243563).

The spelling of 20321131261 in words is "twenty billion, three hundred twenty-one million, one hundred thirty-one thousand, two hundred sixty-one".