21003302261 has 2 divisors, whose sum is σ = 21003302262. Its totient is φ = 21003302260.

The previous prime is 21003302231. The next prime is 21003302263. The reversal of 21003302261 is 16220330012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12297479236 + 8705823025 = 110894^2 + 93305^2 .

It is a cyclic number.

It is not a de Polignac number, because 21003302261 - 2⁶ = 21003302197 is a prime.

It is a super-2 number, since 2×21003302261² (a number of 21 digits) contains 22 as substring.

Together with 21003302263, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21003302263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501651130 + 10501651131.

It is an arithmetic number, because the mean of its divisors is an integer number (10501651131).

Almost surely, 2^21003302261 is an apocalyptic number.

It is an amenable number.

21003302261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003302261 is an equidigital number, since it uses as much as digits as its factorization.

21003302261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21003302261 its reverse (16220330012), we get a palindrome (37223632273).

The spelling of 21003302261 in words is "twenty-one billion, three million, three hundred two thousand, two hundred sixty-one".