21368459 has 6 divisors (see below), whose sum is σ = 24857244. Its totient is φ = 18315780.

The previous prime is 21368453. The next prime is 21368461. The reversal of 21368459 is 95486312.

It is a happy number.

It is not a de Polignac number, because 21368459 - 2¹⁶ = 21302923 is a prime.

It is a super-2 number, since 2×21368459² = 913222080069362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21368453) 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 in 5 ways as a sum of consecutive naturals, for example, 217997 + ... + 218094.

It is an arithmetic number, because the mean of its divisors is an integer number (4142874).

Almost surely, 2^21368459 is an apocalyptic number.

21368459 is a deficient number, since it is larger than the sum of its proper divisors (3488785).

21368459 is an equidigital number, since it uses as much as digits as its factorization.

21368459 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436105 (or 436098 counting only the distinct ones).

The product of its digits is 51840, while the sum is 38.

The square root of 21368459 is about 4622.6030545570. The cubic root of 21368459 is about 277.4966436301.

The spelling of 21368459 in words is "twenty-one million, three hundred sixty-eight thousand, four hundred fifty-nine".