20210120221 has 2 divisors, whose sum is σ = 20210120222. Its totient is φ = 20210120220.

The previous prime is 20210120197. The next prime is 20210120233. The reversal of 20210120221 is 12202101202.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17387323321 + 2822796900 = 131861^2 + 53130^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20210120221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20210120321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105060110 + 10105060111.

It is an arithmetic number, because the mean of its divisors is an integer number (10105060111).

Almost surely, 2^20210120221 is an apocalyptic number.

It is an amenable number.

20210120221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20210120221 is an equidigital number, since it uses as much as digits as its factorization.

20210120221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 20210120221 its reverse (12202101202), we get a palindrome (32412221423).

The spelling of 20210120221 in words is "twenty billion, two hundred ten million, one hundred twenty thousand, two hundred twenty-one".