21336556 has 12 divisors (see below), whose sum is σ = 38543680. Its totient is φ = 10324080.

The previous prime is 21336551. The next prime is 21336559. The reversal of 21336556 is 65563312.

It is a super-2 number, since 2×21336556² = 910497243882272, which contains 22 as substring.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is not an unprimeable number, because it can be changed into a prime (21336551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85911 + ... + 86158.

Almost surely, 2^21336556 is an apocalyptic number.

It is an amenable number.

21336556 is a deficient number, since it is larger than the sum of its proper divisors (17207124).

21336556 is a wasteful number, since it uses less digits than its factorization.

21336556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172104 (or 172102 counting only the distinct ones).

The product of its digits is 16200, while the sum is 31.

The square root of 21336556 is about 4619.1510042431. The cubic root of 21336556 is about 277.3584744888.

Adding to 21336556 its reverse (65563312), we get a palindrome (86899868).

The spelling of 21336556 in words is "twenty-one million, three hundred thirty-six thousand, five hundred fifty-six".