21049985 has 8 divisors (see below), whose sum is σ = 27556416. Its totient is φ = 15309040.

The previous prime is 21049949. The next prime is 21050011. The reversal of 21049985 is 58994012.

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

It is not a de Polignac number, because 21049985 - 2⁸ = 21049729 is a prime.

It is a Duffinian number.

It is a Curzon 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, 191309 + ... + 191418.

It is an arithmetic number, because the mean of its divisors is an integer number (3444552).

Almost surely, 2^21049985 is an apocalyptic number.

It is an amenable number.

21049985 is a deficient number, since it is larger than the sum of its proper divisors (6506431).

21049985 is a wasteful number, since it uses less digits than its factorization.

21049985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382743.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 21049985 is about 4588.0262640922. The cubic root of 21049985 is about 276.1111407397. Note that the first 4 decimals are identical.

The spelling of 21049985 in words is "twenty-one million, forty-nine thousand, nine hundred eighty-five".