21399395 has 4 divisors (see below), whose sum is σ = 25679280. Its totient is φ = 17119512.

The previous prime is 21399353. The next prime is 21399401. The reversal of 21399395 is 59399312.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21399395 - 2¹⁰ = 21398371 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2139935 + ... + 2139944.

It is an arithmetic number, because the mean of its divisors is an integer number (6419820).

Almost surely, 2^21399395 is an apocalyptic number.

21399395 is a deficient number, since it is larger than the sum of its proper divisors (4279885).

21399395 is an equidigital number, since it uses as much as digits as its factorization.

21399395 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4279884.

The product of its digits is 65610, while the sum is 41.

The square root of 21399395 is about 4625.9480109487. The cubic root of 21399395 is about 277.6304935054.

The spelling of 21399395 in words is "twenty-one million, three hundred ninety-nine thousand, three hundred ninety-five".