22405 has 4 divisors (see below), whose sum is σ = 26892. Its totient is φ = 17920.
The previous prime is 22397. The next prime is 22409. The reversal of 22405 is 50422.
It is a happy number.
It is a semiprime because it is the product of two primes.
It can be written as a sum of positive squares in 2 ways, for example, as 12996 + 9409 = 114^2 + 97^2 .
It is not a de Polignac number, because 22405 - 23 = 22397 is a prime.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (22409) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2236 + ... + 2245.
It is an arithmetic number, because the mean of its divisors is an integer number (6723).
222405 is an apocalyptic number.
It is an amenable number.
22405 is a deficient number, since it is larger than the sum of its proper divisors (4487).
22405 is an equidigital number, since it uses as much as digits as its factorization.
22405 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 4486.
The product of its (nonzero) digits is 80, while the sum is 13.
The square root of 22405 is about 149.6829983665. The cubic root of 22405 is about 28.1912921826.
Adding to 22405 its reverse (50422), we get a palindrome (72827).
The spelling of 22405 in words is "twenty-two thousand, four hundred five".
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