21561106 has 8 divisors (see below), whose sum is σ = 36961920. Its totient is φ = 9240468.

The previous prime is 21561101. The next prime is 21561107. The reversal of 21561106 is 60116512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21561101) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 770026 + ... + 770053.

It is an arithmetic number, because the mean of its divisors is an integer number (4620240).

Almost surely, 2^21561106 is an apocalyptic number.

21561106 is a deficient number, since it is larger than the sum of its proper divisors (15400814).

21561106 is a wasteful number, since it uses less digits than its factorization.

21561106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540088.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 21561106 is about 4643.3938019513. The cubic root of 21561106 is about 278.3280722190.

Adding to 21561106 its reverse (60116512), we get a palindrome (81677618).

The spelling of 21561106 in words is "twenty-one million, five hundred sixty-one thousand, one hundred six".