20001221231 has 2 divisors, whose sum is σ = 20001221232. Its totient is φ = 20001221230.

The previous prime is 20001221171. The next prime is 20001221281. The reversal of 20001221231 is 13212210002.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20001221231 - 2¹⁰ = 20001220207 is a prime.

It is a super-2 number, since 2×20001221231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20001221281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000610615 + 10000610616.

It is an arithmetic number, because the mean of its divisors is an integer number (10000610616).

Almost surely, 2^20001221231 is an apocalyptic number.

20001221231 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001221231 is an equidigital number, since it uses as much as digits as its factorization.

20001221231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 20001221231 its reverse (13212210002), we get a palindrome (33213431233).

The spelling of 20001221231 in words is "twenty billion, one million, two hundred twenty-one thousand, two hundred thirty-one".