21200743021 has 2 divisors, whose sum is σ = 21200743022. Its totient is φ = 21200743020.

The previous prime is 21200742991. The next prime is 21200743043. The reversal of 21200743021 is 12034700212.

It is an a-pointer prime, because the next prime (21200743043) can be obtained adding 21200743021 to its sum of digits (22).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20457580900 + 743162121 = 143030^2 + 27261^2 .

It is a cyclic number.

It is not a de Polignac number, because 21200743021 - 2¹⁹ = 21200218733 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21200742983 and 21200743001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21200743121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600371510 + 10600371511.

It is an arithmetic number, because the mean of its divisors is an integer number (10600371511).

Almost surely, 2^21200743021 is an apocalyptic number.

It is an amenable number.

21200743021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21200743021 is an equidigital number, since it uses as much as digits as its factorization.

21200743021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 22.

The spelling of 21200743021 in words is "twenty-one billion, two hundred million, seven hundred forty-three thousand, twenty-one".