20994881 has 8 divisors (see below), whose sum is σ = 22346280. Its totient is φ = 19656448.

The previous prime is 20994863. The next prime is 20994887. The reversal of 20994881 is 18849902.

It can be written as a sum of positive squares in 4 ways, for example, as 10137856 + 10857025 = 3184^2 + 3295^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20994881 - 2¹⁰ = 20993857 is a prime.

It is a super-2 number, since 2×20994881² = 881570056408322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20994887) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 215 + ... + 6483.

It is an arithmetic number, because the mean of its divisors is an integer number (2793285).

Almost surely, 2^20994881 is an apocalyptic number.

It is an amenable number.

20994881 is a deficient number, since it is larger than the sum of its proper divisors (1351399).

20994881 is a wasteful number, since it uses less digits than its factorization.

20994881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6483.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 20994881 is about 4582.0171322246. The cubic root of 20994881 is about 275.8699984626.

The spelling of 20994881 in words is "twenty million, nine hundred ninety-four thousand, eight hundred eighty-one".