21470405 has 16 divisors (see below), whose sum is σ = 29761344. Its totient is φ = 14695680.

The previous prime is 21470389. The next prime is 21470417. The reversal of 21470405 is 50407412.

It is not a de Polignac number, because 21470405 - 2⁴ = 21470389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10547 + ... + 12416.

It is an arithmetic number, because the mean of its divisors is an integer number (1860084).

Almost surely, 2^21470405 is an apocalyptic number.

It is an amenable number.

21470405 is a deficient number, since it is larger than the sum of its proper divisors (8290939).

21470405 is a wasteful number, since it uses less digits than its factorization.

21470405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22996.

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 21470405 is about 4633.6168378492. The cubic root of 21470405 is about 277.9372432224.

Adding to 21470405 its reverse (50407412), we get a palindrome (71877817).

The spelling of 21470405 in words is "twenty-one million, four hundred seventy thousand, four hundred five".