20643433 has 4 divisors (see below), whose sum is σ = 20748420. Its totient is φ = 20538448.

The previous prime is 20643431. The next prime is 20643439. The reversal of 20643433 is 33434602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 33434602 = 2 ⋅16717301.

It can be written as a sum of positive squares in 2 ways, for example, as 10067929 + 10575504 = 3173^2 + 3252^2 .

It is a cyclic number.

It is not a de Polignac number, because 20643433 - 2¹ = 20643431 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20643398 and 20643407.

It is not an unprimeable number, because it can be changed into a prime (20643431) 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, 52198 + ... + 52591.

It is an arithmetic number, because the mean of its divisors is an integer number (5187105).

Almost surely, 2^20643433 is an apocalyptic number.

It is an amenable number.

20643433 is a deficient number, since it is larger than the sum of its proper divisors (104987).

20643433 is a wasteful number, since it uses less digits than its factorization.

20643433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104986.

The product of its (nonzero) digits is 5184, while the sum is 25.

The square root of 20643433 is about 4543.5044844261. The cubic root of 20643433 is about 274.3220014279.

The spelling of 20643433 in words is "twenty million, six hundred forty-three thousand, four hundred thirty-three".