21106885 has 8 divisors (see below), whose sum is σ = 25385976. Its totient is φ = 16847040.

The previous prime is 21106873. The next prime is 21106907. The reversal of 21106885 is 58860112.

It can be written as a sum of positive squares in 4 ways, for example, as 11236 + 21095649 = 106^2 + 4593^2 .

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

It is not a de Polignac number, because 21106885 - 2⁹ = 21106373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2274 + ... + 6883.

It is an arithmetic number, because the mean of its divisors is an integer number (3173247).

Almost surely, 2^21106885 is an apocalyptic number.

It is an amenable number.

21106885 is a deficient number, since it is larger than the sum of its proper divisors (4279091).

21106885 is an equidigital number, since it uses as much as digits as its factorization.

21106885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9623.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 21106885 is about 4594.2230028591. The cubic root of 21106885 is about 276.3597013173.

Adding to 21106885 its reverse (58860112), we get a palindrome (79966997).

The spelling of 21106885 in words is "twenty-one million, one hundred six thousand, eight hundred eighty-five".