20642243 has 4 divisors (see below), whose sum is σ = 20672808. Its totient is φ = 20611680.

The previous prime is 20642239. The next prime is 20642257. The reversal of 20642243 is 34224602.

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 20642243 - 2² = 20642239 is a prime.

It is a super-2 number, since 2×20642243² = 852204392142098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20642213) 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, 14246 + ... + 15627.

It is an arithmetic number, because the mean of its divisors is an integer number (5168202).

Almost surely, 2^20642243 is an apocalyptic number.

20642243 is a deficient number, since it is larger than the sum of its proper divisors (30565).

20642243 is an equidigital number, since it uses as much as digits as its factorization.

20642243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30564.

The product of its (nonzero) digits is 2304, while the sum is 23.

The square root of 20642243 is about 4543.3735263568. The cubic root of 20642243 is about 274.3167301882.

Adding to 20642243 its reverse (34224602), we get a palindrome (54866845).

The spelling of 20642243 in words is "twenty million, six hundred forty-two thousand, two hundred forty-three".