201220211221021 has 16 divisors (see below), whose sum is σ = 206222666929776. Its totient is φ = 196222279680000.

The previous prime is 201220211220989. The next prime is 201220211221067. The reversal of 201220211221021 is 120122112022102.

It can be written as a sum of positive squares in 8 ways, for example, as 1837621536921 + 199382589684100 = 1355589^2 + 14120290^2 .

It is a cyclic number.

It is not a de Polignac number, because 201220211221021 - 2⁵ = 201220211220989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 201220211221021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201220211225021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 983951101 + ... + 984155581.

It is an arithmetic number, because the mean of its divisors is an integer number (12888916683111).

Almost surely, 2^{201220211221021} is an apocalyptic number.

It is an amenable number.

201220211221021 is a deficient number, since it is larger than the sum of its proper divisors (5002455708755).

201220211221021 is a wasteful number, since it uses less digits than its factorization.

201220211221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215424.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 201220211221021 its reverse (120122112022102), we get a palindrome (321342323243123).

The spelling of 201220211221021 in words is "two hundred one trillion, two hundred twenty billion, two hundred eleven million, two hundred twenty-one thousand, twenty-one".