20973818 has 8 divisors (see below), whose sum is σ = 33311412. Its totient is φ = 9870016.

The previous prime is 20973803. The next prime is 20973833. The reversal of 20973818 is 81837902.

It is an interprime number because it is at equal distance from previous prime (20973803) and next prime (20973833).

It can be written as a sum of positive squares in 2 ways, for example, as 20187049 + 786769 = 4493^2 + 887^2 .

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

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 308405 + ... + 308472.

Almost surely, 2^20973818 is an apocalyptic number.

20973818 is a deficient number, since it is larger than the sum of its proper divisors (12337594).

20973818 is a wasteful number, since it uses less digits than its factorization.

20973818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616896.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 20973818 is about 4579.7181135961. The cubic root of 20973818 is about 275.7777125696. Note that the first 4 decimals are identical.

The spelling of 20973818 in words is "twenty million, nine hundred seventy-three thousand, eight hundred eighteen".