21395 has 8 divisors (see below), whose sum is σ = 28080. Its totient is φ = 15520.

The previous prime is 21391. The next prime is 21397. The reversal of 21395 is 59312.

21395 = T₉₀ + T₉₁ + ... + T₉₄.

21395 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 21395 - 2² = 21391 is a prime.

21395 is strictly pandigital in base 6.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 140 + ... + 249.

It is an arithmetic number, because the mean of its divisors is an integer number (3510).

2²¹³⁹⁵ is an apocalyptic number.

21395 is a deficient number, since it is larger than the sum of its proper divisors (6685).

21395 is a wasteful number, since it uses less digits than its factorization.

21395 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 405.

The product of its digits is 270, while the sum is 20.

The square root of 21395 is about 146.2702977368. The cubic root of 21395 is about 27.7611485654.

The spelling of 21395 in words is "twenty-one thousand, three hundred ninety-five".