21906303569 has 2 divisors, whose sum is σ = 21906303570. Its totient is φ = 21906303568.

The previous prime is 21906303457. The next prime is 21906303571. The reversal of 21906303569 is 96530360912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18472343569 + 3433960000 = 135913^2 + 58600^2 .

It is a cyclic number.

It is not a de Polignac number, because 21906303569 - 2¹⁶ = 21906238033 is a prime.

It is a super-2 number, since 2×21906303569² (a number of 21 digits) contains 22 as substring.

Together with 21906303571, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21906300569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10953151784 + 10953151785.

It is an arithmetic number, because the mean of its divisors is an integer number (10953151785).

Almost surely, 2^21906303569 is an apocalyptic number.

It is an amenable number.

21906303569 is a deficient number, since it is larger than the sum of its proper divisors (1).

21906303569 is an equidigital number, since it uses as much as digits as its factorization.

21906303569 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 262440, while the sum is 44.

The spelling of 21906303569 in words is "twenty-one billion, nine hundred six million, three hundred three thousand, five hundred sixty-nine".