20018002021 has 2 divisors, whose sum is σ = 20018002022. Its totient is φ = 20018002020.

The previous prime is 20018001977. The next prime is 20018002097. The reversal of 20018002021 is 12020081002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16329261796 + 3688740225 = 127786^2 + 60735^2 .

It is a cyclic number.

It is not a de Polignac number, because 20018002021 - 2²⁷ = 19883784293 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20018001986 and 20018002004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20018902021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10009001010 + 10009001011.

It is an arithmetic number, because the mean of its divisors is an integer number (10009001011).

Almost surely, 2^20018002021 is an apocalyptic number.

It is an amenable number.

20018002021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20018002021 is an equidigital number, since it uses as much as digits as its factorization.

20018002021 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 16.

Adding to 20018002021 its reverse (12020081002), we get a palindrome (32038083023).

The spelling of 20018002021 in words is "twenty billion, eighteen million, two thousand, twenty-one".