21546556 has 6 divisors (see below), whose sum is σ = 37706480. Its totient is φ = 10773276.

The previous prime is 21546533. The next prime is 21546557. The reversal of 21546556 is 65564512.

It is a super-2 number, since 2×21546556² = 928508150922272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21546557) by changing a digit.

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 as a sum of consecutive naturals, namely, 2693316 + ... + 2693323.

Almost surely, 2^21546556 is an apocalyptic number.

It is an amenable number.

21546556 is a deficient number, since it is larger than the sum of its proper divisors (16159924).

21546556 is a wasteful number, since it uses less digits than its factorization.

21546556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5386643 (or 5386641 counting only the distinct ones).

The product of its digits is 36000, while the sum is 34.

The square root of 21546556 is about 4641.8267955623. The cubic root of 21546556 is about 278.2654504355.

The spelling of 21546556 in words is "twenty-one million, five hundred forty-six thousand, five hundred fifty-six".