20730643 has 4 divisors (see below), whose sum is σ = 20742568. Its totient is φ = 20718720.

The previous prime is 20730623. The next prime is 20730719. The reversal of 20730643 is 34603702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20730643 - 2⁹ = 20730131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20730623) 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, 2793 + ... + 7018.

It is an arithmetic number, because the mean of its divisors is an integer number (5185642).

Almost surely, 2^20730643 is an apocalyptic number.

20730643 is a deficient number, since it is larger than the sum of its proper divisors (11925).

20730643 is an equidigital number, since it uses as much as digits as its factorization.

20730643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11924.

The product of its (nonzero) digits is 3024, while the sum is 25.

The square root of 20730643 is about 4553.0915870428. The cubic root of 20730643 is about 274.7077578642.

The spelling of 20730643 in words is "twenty million, seven hundred thirty thousand, six hundred forty-three".