21398269 has 8 divisors (see below), whose sum is σ = 21982968. Its totient is φ = 20816640.

The previous prime is 21398261. The next prime is 21398281. The reversal of 21398269 is 96289312.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3378244 + 18020025 = 1838^2 + 4245^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21398269 - 2³ = 21398261 is a prime.

It is a super-2 number, since 2×21398269² = 915771832392722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21398261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22369 + ... + 23305.

It is an arithmetic number, because the mean of its divisors is an integer number (2747871).

Almost surely, 2^21398269 is an apocalyptic number.

It is an amenable number.

21398269 is a deficient number, since it is larger than the sum of its proper divisors (584699).

21398269 is an equidigital number, since it uses as much as digits as its factorization.

21398269 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1535.

The product of its digits is 46656, while the sum is 40.

The square root of 21398269 is about 4625.8263045644. The cubic root of 21398269 is about 277.6256239376.

The spelling of 21398269 in words is "twenty-one million, three hundred ninety-eight thousand, two hundred sixty-nine".