20643359 has 4 divisors (see below), whose sum is σ = 22520040. Its totient is φ = 18766680.

The previous prime is 20643353. The next prime is 20643379. The reversal of 20643359 is 95334602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20643359 - 2²⁴ = 3866143 is a prime.

It is a super-2 number, since 2×20643359² = 852296541605762, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20643353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 938324 + ... + 938345.

It is an arithmetic number, because the mean of its divisors is an integer number (5630010).

Almost surely, 2^20643359 is an apocalyptic number.

20643359 is a deficient number, since it is larger than the sum of its proper divisors (1876681).

20643359 is a wasteful number, since it uses less digits than its factorization.

20643359 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1876680.

The product of its (nonzero) digits is 19440, while the sum is 32.

The square root of 20643359 is about 4543.4963409251. The cubic root of 20643359 is about 274.3216736425.

The spelling of 20643359 in words is "twenty million, six hundred forty-three thousand, three hundred fifty-nine".