21307469 has 2 divisors, whose sum is σ = 21307470. Its totient is φ = 21307468.

The previous prime is 21307457. The next prime is 21307487. The reversal of 21307469 is 96470312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20593444 + 714025 = 4538^2 + 845^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21307469 is a prime.

It is a super-2 number, since 2×21307469² = 908016470371922, 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 (21307369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10653734 + 10653735.

It is an arithmetic number, because the mean of its divisors is an integer number (10653735).

Almost surely, 2^21307469 is an apocalyptic number.

It is an amenable number.

21307469 is a deficient number, since it is larger than the sum of its proper divisors (1).

21307469 is an equidigital number, since it uses as much as digits as its factorization.

21307469 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 21307469 is about 4616.0014081454. The cubic root of 21307469 is about 277.2323811190.

The spelling of 21307469 in words is "twenty-one million, three hundred seven thousand, four hundred sixty-nine".