21360556 has 12 divisors (see below), whose sum is σ = 42721168. Its totient is φ = 9154512.

The previous prime is 21360533. The next prime is 21360571. The reversal of 21360556 is 65506312.

21360556 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 762877 = 21360556 / (2 + 1 + 3 + 6 + 0 + 5 + 5 + 6).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 381411 + ... + 381466.

Almost surely, 2^21360556 is an apocalyptic number.

It is an amenable number.

21360556 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21360556 is a wasteful number, since it uses less digits than its factorization.

21360556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 762888 (or 762886 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 21360556 is about 4621.7481541079. The cubic root of 21360556 is about 277.4624292397.

Adding to 21360556 its reverse (65506312), we get a palindrome (86866868).

The spelling of 21360556 in words is "twenty-one million, three hundred sixty thousand, five hundred fifty-six".