21374 has 4 divisors (see below), whose sum is σ = 32064. Its totient is φ = 10686.

The previous prime is 21347. The next prime is 21377. The reversal of 21374 is 47312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21377) by changing a digit.

21374 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5342 + ... + 5345.

It is an arithmetic number, because the mean of its divisors is an integer number (8016).

2²¹³⁷⁴ is an apocalyptic number.

21374 is a deficient number, since it is larger than the sum of its proper divisors (10690).

21374 is a wasteful number, since it uses less digits than its factorization.

21374 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10689.

The product of its digits is 168, while the sum is 17.

The square root of 21374 is about 146.1984952043. The cubic root of 21374 is about 27.7520627204.

Adding to 21374 its reverse (47312), we get a palindrome (68686).

The spelling of 21374 in words is "twenty-one thousand, three hundred seventy-four", and thus it is an iban number.