20643938 has 16 divisors (see below), whose sum is σ = 35722944. Its totient is φ = 8764080.

The previous prime is 20643907. The next prime is 20643941. The reversal of 20643938 is 83934602.

It is a happy number.

It is a super-2 number, since 2×20643938² = 852344352295688, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20643898 and 20643907.

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, 5393 + ... + 8388.

It is an arithmetic number, because the mean of its divisors is an integer number (2232684).

Almost surely, 2^20643938 is an apocalyptic number.

20643938 is a deficient number, since it is larger than the sum of its proper divisors (15079006).

20643938 is a wasteful number, since it uses less digits than its factorization.

20643938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13897.

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 20643938 is about 4543.5600579281. The cubic root of 20643938 is about 274.3242383214.

It can be divided in two parts, 206 and 43938, that added together give a palindrome (44144).

The spelling of 20643938 in words is "twenty million, six hundred forty-three thousand, nine hundred thirty-eight".