21842969 has 2 divisors, whose sum is σ = 21842970. Its totient is φ = 21842968.

The previous prime is 21842963. The next prime is 21842971. The reversal of 21842969 is 96924812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11526025 + 10316944 = 3395^2 + 3212^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21842969 is a prime.

It is a super-2 number, since 2×21842969² = 954230589469922, which contains 22 as substring.

Together with 21842971, 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 (21842963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10921484 + 10921485.

It is an arithmetic number, because the mean of its divisors is an integer number (10921485).

Almost surely, 2^21842969 is an apocalyptic number.

It is an amenable number.

21842969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21842969 is an equidigital number, since it uses as much as digits as its factorization.

21842969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 41.

The square root of 21842969 is about 4673.6462210998. The cubic root of 21842969 is about 279.5356632179.

The spelling of 21842969 in words is "twenty-one million, eight hundred forty-two thousand, nine hundred sixty-nine".