13205421 has 12 divisors (see below), whose sum is σ = 19146972. Its totient is φ = 8770176.

The previous prime is 13205419. The next prime is 13205461. The reversal of 13205421 is 12450231.

It can be written as a sum of positive squares in 2 ways, for example, as 6502500 + 6702921 = 2550^2 + 2589^2 .

It is not a de Polignac number, because 13205421 - 2¹ = 13205419 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 13205394 and 13205403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13205461) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 156 + ... + 5141.

It is an arithmetic number, because the mean of its divisors is an integer number (1595581).

Almost surely, 2^13205421 is an apocalyptic number.

It is an amenable number.

13205421 is a deficient number, since it is larger than the sum of its proper divisors (5941551).

13205421 is a wasteful number, since it uses less digits than its factorization.

13205421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5580 (or 5577 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 13205421 is about 3633.9263889077. The cubic root of 13205421 is about 236.3654982416.

Adding to 13205421 its reverse (12450231), we get a palindrome (25655652).

The spelling of 13205421 in words is "thirteen million, two hundred five thousand, four hundred twenty-one".