21403231121 has 2 divisors, whose sum is σ = 21403231122. Its totient is φ = 21403231120.

The previous prime is 21403231067. The next prime is 21403231147. The reversal of 21403231121 is 12113230412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21029350225 + 373880896 = 145015^2 + 19336^2 .

It is a cyclic number.

It is not a de Polignac number, because 21403231121 - 2¹⁰ = 21403230097 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21403231093 and 21403231102.

It is not a weakly prime, because it can be changed into another prime (21403231621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701615560 + 10701615561.

It is an arithmetic number, because the mean of its divisors is an integer number (10701615561).

Almost surely, 2^21403231121 is an apocalyptic number.

It is an amenable number.

21403231121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403231121 is an equidigital number, since it uses as much as digits as its factorization.

21403231121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 21403231121 its reverse (12113230412), we get a palindrome (33516461533).

The spelling of 21403231121 in words is "twenty-one billion, four hundred three million, two hundred thirty-one thousand, one hundred twenty-one".