21160556 has 12 divisors (see below), whose sum is σ = 37553040. Its totient is φ = 10431120.

The previous prime is 21160553. The next prime is 21160571. The reversal of 21160556 is 65506112.

It is not an unprimeable number, because it can be changed into a prime (21160553) 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 in 3 ways as a sum of consecutive naturals, for example, 36971 + ... + 37538.

It is an arithmetic number, because the mean of its divisors is an integer number (3129420).

Almost surely, 2^21160556 is an apocalyptic number.

It is an amenable number.

21160556 is a deficient number, since it is larger than the sum of its proper divisors (16392484).

21160556 is a wasteful number, since it uses less digits than its factorization.

21160556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74584 (or 74582 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 21160556 is about 4600.0604343856. The cubic root of 21160556 is about 276.5937473349.

Adding to 21160556 its reverse (65506112), we get a palindrome (86666668).

The spelling of 21160556 in words is "twenty-one million, one hundred sixty thousand, five hundred fifty-six".