21407 has 2 divisors, whose sum is σ = 21408. Its totient is φ = 21406.
The previous prime is 21401. The next prime is 21419. The reversal of 21407 is 70412.
It is a happy number.
It is a weak prime.
It is a cyclic number.
It is not a de Polignac number, because 21407 - 24 = 21391 is a prime.
It is a Chen prime.
It is a nialpdrome in base 15.
It is a junction number, because it is equal to n+sod(n) for n = 21391 and 21400.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 21407.
It is not a weakly prime, because it can be changed into another prime (21401) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10703 + 10704.
It is an arithmetic number, because the mean of its divisors is an integer number (10704).
221407 is an apocalyptic number.
21407 is a deficient number, since it is larger than the sum of its proper divisors (1).
21407 is an equidigital number, since it uses as much as digits as its factorization.
21407 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 56, while the sum is 14.
The square root of 21407 is about 146.3113119345. The cubic root of 21407 is about 27.7663378077.
Adding to 21407 its reverse (70412), we get a palindrome (91819).
The spelling of 21407 in words is "twenty-one thousand, four hundred seven", and thus it is an iban number.
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