20938816 has 28 divisors (see below), whose sum is σ = 42341292. Its totient is φ = 10270208.

The previous prime is 20938811. The next prime is 20938831. The reversal of 20938816 is 61883902.

It can be written as a sum of positive squares in 2 ways, for example, as 5760000 + 15178816 = 2400^2 + 3896^2 .

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (20938811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 306 + ... + 6478.

It is an arithmetic number, because the mean of its divisors is an integer number (1512189).

Almost surely, 2^20938816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20938816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21170646).

20938816 is an abundant number, since it is smaller than the sum of its proper divisors (21402476).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20938816 is an equidigital number, since it uses as much as digits as its factorization.

20938816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6238 (or 6228 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 20938816 is about 4575.8951036928. The cubic root of 20938816 is about 275.6242172906.

The spelling of 20938816 in words is "twenty million, nine hundred thirty-eight thousand, eight hundred sixteen".