20643442 has 4 divisors (see below), whose sum is σ = 30965166. Its totient is φ = 10321720.

The previous prime is 20643439. The next prime is 20643449. The reversal of 20643442 is 24434602.

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

It can be written as a sum of positive squares in only one way, i.e., 19368801 + 1274641 = 4401^2 + 1129^2 .

It is not an unprimeable number, because it can be changed into a prime (20643449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5160859 + ... + 5160862.

Almost surely, 2^20643442 is an apocalyptic number.

20643442 is a deficient number, since it is larger than the sum of its proper divisors (10321724).

20643442 is a wasteful number, since it uses less digits than its factorization.

20643442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10321723.

The product of its (nonzero) digits is 4608, while the sum is 25.

The square root of 20643442 is about 4543.5054748509. The cubic root of 20643442 is about 274.3220412937.

The spelling of 20643442 in words is "twenty million, six hundred forty-three thousand, four hundred forty-two".