20122220021 has 2 divisors, whose sum is σ = 20122220022. Its totient is φ = 20122220020.

The previous prime is 20122220011. The next prime is 20122220029. The reversal of 20122220021 is 12002222102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16068351121 + 4053868900 = 126761^2 + 63670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20122220021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20122219978 and 20122220005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20122220029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10061110010 + 10061110011.

It is an arithmetic number, because the mean of its divisors is an integer number (10061110011).

Almost surely, 2^20122220021 is an apocalyptic number.

It is an amenable number.

20122220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20122220021 is an equidigital number, since it uses as much as digits as its factorization.

20122220021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 20122220021 its reverse (12002222102), we get a palindrome (32124442123).

The spelling of 20122220021 in words is "twenty billion, one hundred twenty-two million, two hundred twenty thousand, twenty-one".