21106616 has 8 divisors (see below), whose sum is σ = 39574920. Its totient is φ = 10553304.

The previous prime is 21106607. The next prime is 21106643. The reversal of 21106616 is 61660112.

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

It is a junction number, because it is equal to n+sod(n) for n = 21106591 and 21106600.

It is a congruent number.

It is an unprimeable number.

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, 1319156 + ... + 1319171.

It is an arithmetic number, because the mean of its divisors is an integer number (4946865).

Almost surely, 2^21106616 is an apocalyptic number.

It is an amenable number.

21106616 is a deficient number, since it is larger than the sum of its proper divisors (18468304).

21106616 is a wasteful number, since it uses less digits than its factorization.

21106616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2638333 (or 2638329 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21106616 is about 4594.1937268687. The cubic root of 21106616 is about 276.3585272759.

Adding to 21106616 its reverse (61660112), we get a palindrome (82766728).

The spelling of 21106616 in words is "twenty-one million, one hundred six thousand, six hundred sixteen".