21470393 has 4 divisors (see below), whose sum is σ = 24537600. Its totient is φ = 18403188.

The previous prime is 21470389. The next prime is 21470417. The reversal of 21470393 is 39307412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21470393 - 2² = 21470389 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21470333) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1533593 + ... + 1533606.

It is an arithmetic number, because the mean of its divisors is an integer number (6134400).

Almost surely, 2^21470393 is an apocalyptic number.

It is an amenable number.

21470393 is a deficient number, since it is larger than the sum of its proper divisors (3067207).

21470393 is an equidigital number, since it uses as much as digits as its factorization.

21470393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3067206.

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 21470393 is about 4633.6155429643. The cubic root of 21470393 is about 277.9371914419.

It can be divided in two parts, 214 and 70393, that added together give a palindrome (70607).

The spelling of 21470393 in words is "twenty-one million, four hundred seventy thousand, three hundred ninety-three".