21561068 has 6 divisors (see below), whose sum is σ = 37731876. Its totient is φ = 10780532.

The previous prime is 21561041. The next prime is 21561077. The reversal of 21561068 is 86016512.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21561068.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2695130 + ... + 2695137.

It is an arithmetic number, because the mean of its divisors is an integer number (6288646).

Almost surely, 2^21561068 is an apocalyptic number.

It is an amenable number.

21561068 is a deficient number, since it is larger than the sum of its proper divisors (16170808).

21561068 is a wasteful number, since it uses less digits than its factorization.

21561068 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5390271 (or 5390269 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 21561068 is about 4643.3897101148. The cubic root of 21561068 is about 278.3279087074.

The spelling of 21561068 in words is "twenty-one million, five hundred sixty-one thousand, sixty-eight".