21865469 has 2 divisors, whose sum is σ = 21865470. Its totient is φ = 21865468.

The previous prime is 21865439. The next prime is 21865531. The reversal of 21865469 is 96456812.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21576025 + 289444 = 4645^2 + 538^2 .

It is a cyclic number.

It is not a de Polignac number, because 21865469 - 2¹² = 21861373 is a prime.

It is a super-2 number, since 2×21865469² = 956197469179922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21865439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10932734 + 10932735.

It is an arithmetic number, because the mean of its divisors is an integer number (10932735).

Almost surely, 2^21865469 is an apocalyptic number.

It is an amenable number.

21865469 is a deficient number, since it is larger than the sum of its proper divisors (1).

21865469 is an equidigital number, since it uses as much as digits as its factorization.

21865469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 103680, while the sum is 41.

The square root of 21865469 is about 4676.0527156994. The cubic root of 21865469 is about 279.6316116224.

The spelling of 21865469 in words is "twenty-one million, eight hundred sixty-five thousand, four hundred sixty-nine".