21123131221427 has 2 divisors, whose sum is σ = 21123131221428. Its totient is φ = 21123131221426.

The previous prime is 21123131221343. The next prime is 21123131221499. The reversal of 21123131221427 is 72412213132112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21123131221427 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21123131221393 and 21123131221402.

It is not a weakly prime, because it can be changed into another prime (21123131221627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561565610713 + 10561565610714.

It is an arithmetic number, because the mean of its divisors is an integer number (10561565610714).

Almost surely, 2^{21123131221427} is an apocalyptic number.

21123131221427 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123131221427 is an equidigital number, since it uses as much as digits as its factorization.

21123131221427 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 32.

Adding to 21123131221427 its reverse (72412213132112), we get a palindrome (93535344353539).

The spelling of 21123131221427 in words is "twenty-one trillion, one hundred twenty-three billion, one hundred thirty-one million, two hundred twenty-one thousand, four hundred twenty-seven".