21424586 has 4 divisors (see below), whose sum is σ = 32136882. Its totient is φ = 10712292.

The previous prime is 21424577. The next prime is 21424589. The reversal of 21424586 is 68542412.

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

It can be written as a sum of positive squares in only one way, i.e., 16248961 + 5175625 = 4031^2 + 2275^2 .

It is not an unprimeable number, because it can be changed into a prime (21424589) 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 as a sum of consecutive naturals, namely, 5356145 + ... + 5356148.

Almost surely, 2^21424586 is an apocalyptic number.

21424586 is a deficient number, since it is larger than the sum of its proper divisors (10712296).

21424586 is a wasteful number, since it uses less digits than its factorization.

21424586 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10712295.

The product of its digits is 15360, while the sum is 32.

The square root of 21424586 is about 4628.6700033595. The cubic root of 21424586 is about 277.7393914008.

Adding to 21424586 its reverse (68542412), we get a palindrome (89966998).

The spelling of 21424586 in words is "twenty-one million, four hundred twenty-four thousand, five hundred eighty-six".