21561112 has 8 divisors (see below), whose sum is σ = 40427100. Its totient is φ = 10780552.

The previous prime is 21561107. The next prime is 21561131. The reversal of 21561112 is 21116512.

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21561112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1347562 + ... + 1347577.

Almost surely, 2^21561112 is an apocalyptic number.

It is an amenable number.

21561112 is a deficient number, since it is larger than the sum of its proper divisors (18865988).

21561112 is a wasteful number, since it uses less digits than its factorization.

21561112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2695145 (or 2695141 counting only the distinct ones).

The product of its digits is 120, while the sum is 19.

The square root of 21561112 is about 4643.3944480304. The cubic root of 21561112 is about 278.3280980366.

Adding to 21561112 its reverse (21116512), we get a palindrome (42677624).

The spelling of 21561112 in words is "twenty-one million, five hundred sixty-one thousand, one hundred twelve".