21043402273 has 2 divisors, whose sum is σ = 21043402274. Its totient is φ = 21043402272.

The previous prime is 21043402241. The next prime is 21043402279. The reversal of 21043402273 is 37220434012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13621924369 + 7421477904 = 116713^2 + 86148^2 .

It is a cyclic number.

It is not a de Polignac number, because 21043402273 - 2⁵ = 21043402241 is a prime.

It is not a weakly prime, because it can be changed into another prime (21043402279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521701136 + 10521701137.

It is an arithmetic number, because the mean of its divisors is an integer number (10521701137).

Almost surely, 2^21043402273 is an apocalyptic number.

It is an amenable number.

21043402273 is a deficient number, since it is larger than the sum of its proper divisors (1).

21043402273 is an equidigital number, since it uses as much as digits as its factorization.

21043402273 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 28.

Adding to 21043402273 its reverse (37220434012), we get a palindrome (58263836285).

The spelling of 21043402273 in words is "twenty-one billion, forty-three million, four hundred two thousand, two hundred seventy-three".