21423413 has 12 divisors (see below), whose sum is σ = 23794764. Its totient is φ = 19272000.

The previous prime is 21423403. The next prime is 21423421. The reversal of 21423413 is 31432412.

It can be written as a sum of positive squares in 2 ways, for example, as 10387729 + 11035684 = 3223^2 + 3322^2 .

It is not a de Polignac number, because 21423413 - 2¹² = 21419317 is a prime.

It is a hoax number, since the sum of its digits (20) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423403) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 11345 + ... + 13097.

It is an arithmetic number, because the mean of its divisors is an integer number (1982897).

Almost surely, 2^21423413 is an apocalyptic number.

It is an amenable number.

21423413 is a deficient number, since it is larger than the sum of its proper divisors (2371351).

21423413 is a wasteful number, since it uses less digits than its factorization.

21423413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1876 (or 1865 counting only the distinct ones).

The product of its digits is 576, while the sum is 20.

The square root of 21423413 is about 4628.5432913607. The cubic root of 21423413 is about 277.7343225475.

Adding to 21423413 its reverse (31432412), we get a palindrome (52855825).

It can be divided in two parts, 2142 and 3413, that added together give a palindrome (5555).

The spelling of 21423413 in words is "twenty-one million, four hundred twenty-three thousand, four hundred thirteen".