21423461 has 4 divisors (see below), whose sum is σ = 21437472. Its totient is φ = 21409452.

The previous prime is 21423421. The next prime is 21423487. The reversal of 21423461 is 16432412.

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 21423461 - 2¹⁸ = 21161317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423421) 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 3 ways as a sum of consecutive naturals, for example, 4385 + ... + 7878.

It is an arithmetic number, because the mean of its divisors is an integer number (5359368).

Almost surely, 2^21423461 is an apocalyptic number.

It is an amenable number.

21423461 is a deficient number, since it is larger than the sum of its proper divisors (14011).

21423461 is a wasteful number, since it uses less digits than its factorization.

21423461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14010.

The product of its digits is 1152, while the sum is 23.

The square root of 21423461 is about 4628.5484765745. The cubic root of 21423461 is about 277.7345299722.

Adding to 21423461 its reverse (16432412), we get a palindrome (37855873).

The spelling of 21423461 in words is "twenty-one million, four hundred twenty-three thousand, four hundred sixty-one".