20643393 has 4 divisors (see below), whose sum is σ = 27524528. Its totient is φ = 13762260.

The previous prime is 20643379. The next prime is 20643407. The reversal of 20643393 is 39334602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (20643379) and next prime (20643407).

It is not a de Polignac number, because 20643393 - 2⁸ = 20643137 is a prime.

It is a super-2 number, since 2×20643393² = 852299349104898, which contains 22 as substring.

It is the 4544-th Hogben number.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20643393.

It is not an unprimeable number, because it can be changed into a prime (20643313) by changing a digit.

It is a nontrivial repunit in base 4543.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3440563 + ... + 3440568.

It is an arithmetic number, because the mean of its divisors is an integer number (6881132).

Almost surely, 2^20643393 is an apocalyptic number.

It is an amenable number.

20643393 is a deficient number, since it is larger than the sum of its proper divisors (6881135).

20643393 is an equidigital number, since it uses as much as digits as its factorization.

20643393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6881134.

The product of its (nonzero) digits is 11664, while the sum is 30.

The square root of 20643393 is about 4543.5000825355. The cubic root of 20643393 is about 274.3218242467.

Adding to 20643393 its reverse (39334602), we get a palindrome (59977995).

The spelling of 20643393 in words is "twenty million, six hundred forty-three thousand, three hundred ninety-three".