20402224021 has 2 divisors, whose sum is σ = 20402224022. Its totient is φ = 20402224020.

The previous prime is 20402224001. The next prime is 20402224027. The reversal of 20402224021 is 12042220402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20371852900 + 30371121 = 142730^2 + 5511^2 .

It is a cyclic number.

It is not a de Polignac number, because 20402224021 - 2⁷ = 20402223893 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20402224021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20402224027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10201112010 + 10201112011.

It is an arithmetic number, because the mean of its divisors is an integer number (10201112011).

Almost surely, 2^20402224021 is an apocalyptic number.

It is an amenable number.

20402224021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20402224021 is an equidigital number, since it uses as much as digits as its factorization.

20402224021 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 19.

Adding to 20402224021 its reverse (12042220402), we get a palindrome (32444444423).

The spelling of 20402224021 in words is "twenty billion, four hundred two million, two hundred twenty-four thousand, twenty-one".