21394 has 8 divisors (see below), whose sum is σ = 33840. Its totient is φ = 10116.

The previous prime is 21391. The next prime is 21397. The reversal of 21394 is 49312.

It is an interprime number because it is at equal distance from previous prime (21391) and next prime (21397).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is not an unprimeable number, because it can be changed into a prime (21391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 244 + ... + 319.

It is an arithmetic number, because the mean of its divisors is an integer number (4230).

2²¹³⁹⁴ is an apocalyptic number.

21394 is a deficient number, since it is larger than the sum of its proper divisors (12446).

21394 is a wasteful number, since it uses less digits than its factorization.

21394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 584.

The product of its digits is 216, while the sum is 19.

The square root of 21394 is about 146.2668793678. The cubic root of 21394 is about 27.7607160410.

The spelling of 21394 in words is "twenty-one thousand, three hundred ninety-four".