21413 has 12 divisors (see below), whose sum is σ = 27360. Its totient is φ = 16632.

The previous prime is 21407. The next prime is 21419. The reversal of 21413 is 31412.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21407) and next prime (21419).

It is not a de Polignac number, because 21413 - 2⁴ = 21397 is a prime.

It is an Ulam number.

It is a nialpdrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 21394 and 21403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21419) 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, 920 + ... + 942.

It is an arithmetic number, because the mean of its divisors is an integer number (2280).

2²¹⁴¹³ is an apocalyptic number.

21413 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21413 is a deficient number, since it is larger than the sum of its proper divisors (5947).

21413 is a wasteful number, since it uses less digits than its factorization.

21413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56 (or 49 counting only the distinct ones).

The product of its digits is 24, while the sum is 11.

The square root of 21413 is about 146.3318147226. The cubic root of 21413 is about 27.7689317017.

Adding to 21413 its reverse (31412), we get a palindrome (52825).

Subtracting 21413 from its reverse (31412), we obtain a palindrome (9999).

It can be divided in two parts, 21 and 413, that added together give a palindrome (434).

The spelling of 21413 in words is "twenty-one thousand, four hundred thirteen".