21424628 has 36 divisors (see below), whose sum is σ = 40741092. Its totient is φ = 9849600.

The previous prime is 21424619. The next prime is 21424631. The reversal of 21424628 is 82642412.

It can be written as a sum of positive squares in 2 ways, for example, as 20448484 + 976144 = 4522^2 + 988^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21424628.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53228 + ... + 53628.

It is an arithmetic number, because the mean of its divisors is an integer number (1131697).

Almost surely, 2^21424628 is an apocalyptic number.

It is an amenable number.

21424628 is a deficient number, since it is larger than the sum of its proper divisors (19316464).

21424628 is a wasteful number, since it uses less digits than its factorization.

21424628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480 (or 459 counting only the distinct ones).

The product of its digits is 6144, while the sum is 29.

The square root of 21424628 is about 4628.6745402977. The cubic root of 21424628 is about 277.7395728908.

It can be divided in two parts, 214 and 24628, that added together give a palindrome (24842).

The spelling of 21424628 in words is "twenty-one million, four hundred twenty-four thousand, six hundred twenty-eight".