21104985 has 32 divisors (see below), whose sum is σ = 37844352. Its totient is φ = 9953280.

The previous prime is 21104981. The next prime is 21104989. The reversal of 21104985 is 58940112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21104981) and next prime (21104989).

It is not a de Polignac number, because 21104985 - 2² = 21104981 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21104981) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4377 + ... + 7833.

It is an arithmetic number, because the mean of its divisors is an integer number (1182636).

Almost surely, 2^21104985 is an apocalyptic number.

It is an amenable number.

21104985 is a deficient number, since it is larger than the sum of its proper divisors (16739367).

21104985 is a wasteful number, since it uses less digits than its factorization.

21104985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3513.

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 21104985 is about 4594.0162167759. The cubic root of 21104985 is about 276.3514086174.

The spelling of 21104985 in words is "twenty-one million, one hundred four thousand, nine hundred eighty-five".