21403442111021 has 2 divisors, whose sum is σ = 21403442111022. Its totient is φ = 21403442111020.

The previous prime is 21403442110987. The next prime is 21403442111033. The reversal of 21403442111021 is 12011124430412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13544895154921 + 7858546956100 = 3680339^2 + 2803310^2 .

It is a cyclic number.

It is not a de Polignac number, because 21403442111021 - 2²⁶ = 21403375002157 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21403442117021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701721055510 + 10701721055511.

It is an arithmetic number, because the mean of its divisors is an integer number (10701721055511).

Almost surely, 2^{21403442111021} is an apocalyptic number.

It is an amenable number.

21403442111021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403442111021 is an equidigital number, since it uses as much as digits as its factorization.

21403442111021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1536, while the sum is 26.

Adding to 21403442111021 its reverse (12011124430412), we get a palindrome (33414566541433).

The spelling of 21403442111021 in words is "twenty-one trillion, four hundred three billion, four hundred forty-two million, one hundred eleven thousand, twenty-one".