21603628 has 12 divisors (see below), whose sum is σ = 38005632. Its totient is φ = 10744880.

The previous prime is 21603613. The next prime is 21603643. The reversal of 21603628 is 82630612.

It is an interprime number because it is at equal distance from previous prime (21603613) and next prime (21603643).

It is a junction number, because it is equal to n+sod(n) for n = 21603596 and 21603605.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13375 + ... + 14902.

It is an arithmetic number, because the mean of its divisors is an integer number (3167136).

Almost surely, 2^21603628 is an apocalyptic number.

It is an amenable number.

21603628 is a deficient number, since it is larger than the sum of its proper divisors (16402004).

21603628 is a wasteful number, since it uses less digits than its factorization.

21603628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28472 (or 28470 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21603628 is about 4647.9703097158. The cubic root of 21603628 is about 278.5109214441.

The spelling of 21603628 in words is "twenty-one million, six hundred three thousand, six hundred twenty-eight".