201021221021 has 4 divisors (see below), whose sum is σ = 201023218044. Its totient is φ = 201019224000.

The previous prime is 201021220993. The next prime is 201021221161. The reversal of 201021221021 is 120122120102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 55391976025 + 145629244996 = 235355^2 + 381614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201021221021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201021220987 and 201021221005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201021220021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 839030 + ... + 1051671.

It is an arithmetic number, because the mean of its divisors is an integer number (50255804511).

Almost surely, 2^201021221021 is an apocalyptic number.

It is an amenable number.

201021221021 is a deficient number, since it is larger than the sum of its proper divisors (1997023).

201021221021 is a wasteful number, since it uses less digits than its factorization.

201021221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1997022.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 201021221021 its reverse (120122120102), we get a palindrome (321143341123).

The spelling of 201021221021 in words is "two hundred one billion, twenty-one million, two hundred twenty-one thousand, twenty-one".