20402321243 has 4 divisors (see below), whose sum is σ = 20418299280. Its totient is φ = 20386343208.

The previous prime is 20402321213. The next prime is 20402321257. The reversal of 20402321243 is 34212320402.

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 20402321243 - 2¹⁰ = 20402320219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20402321213) 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, 7987103 + ... + 7989656.

It is an arithmetic number, because the mean of its divisors is an integer number (5104574820).

Almost surely, 2^20402321243 is an apocalyptic number.

20402321243 is a deficient number, since it is larger than the sum of its proper divisors (15978037).

20402321243 is a wasteful number, since it uses less digits than its factorization.

20402321243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15978036.

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

Adding to 20402321243 its reverse (34212320402), we get a palindrome (54614641645).

The spelling of 20402321243 in words is "twenty billion, four hundred two million, three hundred twenty-one thousand, two hundred forty-three".