21432245 has 8 divisors (see below), whose sum is σ = 25747416. Its totient is φ = 17126656.

The previous prime is 21432241. The next prime is 21432259. The reversal of 21432245 is 54223412.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1164241 + 20268004 = 1079^2 + 4502^2 .

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 21432245 - 2² = 21432241 is a prime.

It is a super-2 number, since 2×21432245² = 918682251480050, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21432245.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21432241) 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, 4169 + ... + 7761.

It is an arithmetic number, because the mean of its divisors is an integer number (3218427).

Almost surely, 2^21432245 is an apocalyptic number.

It is an amenable number.

21432245 is a deficient number, since it is larger than the sum of its proper divisors (4315171).

21432245 is a wasteful number, since it uses less digits than its factorization.

21432245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4791.

The product of its digits is 1920, while the sum is 23.

The square root of 21432245 is about 4629.4972729228. The cubic root of 21432245 is about 277.7724834843.

Adding to 21432245 its reverse (54223412), we get a palindrome (75655657).

The spelling of 21432245 in words is "twenty-one million, four hundred thirty-two thousand, two hundred forty-five".