20440143221 has 4 divisors (see below), whose sum is σ = 20440507692. Its totient is φ = 20439778752.

The previous prime is 20440143107. The next prime is 20440143223. The reversal of 20440143221 is 12234104402.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13372378321 + 7067764900 = 115639^2 + 84070^2 .

It is a cyclic number.

It is not a de Polignac number, because 20440143221 - 2³⁴ = 3260274037 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20440143223) 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, 78386 + ... + 216851.

It is an arithmetic number, because the mean of its divisors is an integer number (5110126923).

Almost surely, 2^20440143221 is an apocalyptic number.

It is an amenable number.

20440143221 is a deficient number, since it is larger than the sum of its proper divisors (364471).

20440143221 is an equidigital number, since it uses as much as digits as its factorization.

20440143221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364470.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 20440143221 its reverse (12234104402), we get a palindrome (32674247623).

The spelling of 20440143221 in words is "twenty billion, four hundred forty million, one hundred forty-three thousand, two hundred twenty-one".