21145469 has 2 divisors, whose sum is σ = 21145470. Its totient is φ = 21145468.

The previous prime is 21145451. The next prime is 21145471. The reversal of 21145469 is 96454112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18705625 + 2439844 = 4325^2 + 1562^2 .

It is a cyclic number.

It is not a de Polignac number, because 21145469 - 2⁸ = 21145213 is a prime.

It is a super-2 number, since 2×21145469² = 894261718459922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 21145471, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21145409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572734 + 10572735.

It is an arithmetic number, because the mean of its divisors is an integer number (10572735).

Almost surely, 2^21145469 is an apocalyptic number.

It is an amenable number.

21145469 is a deficient number, since it is larger than the sum of its proper divisors (1).

21145469 is an equidigital number, since it uses as much as digits as its factorization.

21145469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 32.

The square root of 21145469 is about 4598.4202722239. The cubic root of 21145469 is about 276.5279966681.

It can be divided in two parts, 211 and 45469, that multiplied together give a palindrome (9593959).

The spelling of 21145469 in words is "twenty-one million, one hundred forty-five thousand, four hundred sixty-nine".