20643344 has 10 divisors (see below), whose sum is σ = 39996510. Its totient is φ = 10321664.

The previous prime is 20643323. The next prime is 20643347. The reversal of 20643344 is 44334602.

It can be written as a sum of positive squares in only one way, i.e., 13778944 + 6864400 = 3712^2 + 2620^2 .

It is a super-2 number, since 2×20643344² = 852295303004672, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20643347) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645089 + ... + 645120.

It is an arithmetic number, because the mean of its divisors is an integer number (3999651).

Almost surely, 2^20643344 is an apocalyptic number.

It is an amenable number.

20643344 is a deficient number, since it is larger than the sum of its proper divisors (19353166).

20643344 is a wasteful number, since it uses less digits than its factorization.

20643344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1290217 (or 1290211 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 26.

The square root of 20643344 is about 4543.4946902137. The cubic root of 20643344 is about 274.3216071994.

Adding to 20643344 its reverse (44334602), we get a palindrome (64977946).

The spelling of 20643344 in words is "twenty million, six hundred forty-three thousand, three hundred forty-four".