20210221001 has 2 divisors, whose sum is σ = 20210221002. Its totient is φ = 20210221000.

The previous prime is 20210220991. The next prime is 20210221019. The reversal of 20210221001 is 10012201202.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19579005625 + 631215376 = 139925^2 + 25124^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20210221001 is a prime.

It is a super-2 number, since 2×20210221001² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20210223001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105110500 + 10105110501.

It is an arithmetic number, because the mean of its divisors is an integer number (10105110501).

Almost surely, 2^20210221001 is an apocalyptic number.

It is an amenable number.

20210221001 is a deficient number, since it is larger than the sum of its proper divisors (1).

20210221001 is an equidigital number, since it uses as much as digits as its factorization.

20210221001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20210221001 its reverse (10012201202), we get a palindrome (30222422203).

The spelling of 20210221001 in words is "twenty billion, two hundred ten million, two hundred twenty-one thousand, one".