20042142221 has 2 divisors, whose sum is σ = 20042142222. Its totient is φ = 20042142220.

The previous prime is 20042142181. The next prime is 20042142251. The reversal of 20042142221 is 12224124002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19030202500 + 1011939721 = 137950^2 + 31811^2 .

It is a cyclic number.

It is not a de Polignac number, because 20042142221 - 2²⁶ = 19975033357 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20042142193 and 20042142202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20042142251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10021071110 + 10021071111.

It is an arithmetic number, because the mean of its divisors is an integer number (10021071111).

Almost surely, 2^20042142221 is an apocalyptic number.

It is an amenable number.

20042142221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20042142221 is an equidigital number, since it uses as much as digits as its factorization.

20042142221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 20042142221 its reverse (12224124002), we get a palindrome (32266266223).

The spelling of 20042142221 in words is "twenty billion, forty-two million, one hundred forty-two thousand, two hundred twenty-one".