201311021 has 4 divisors (see below), whose sum is σ = 201411132. Its totient is φ = 201210912.

The previous prime is 201311003. The next prime is 201311029. The reversal of 201311021 is 120113102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120113102 = 2 ⋅60056551.

It can be written as a sum of positive squares in 2 ways, for example, as 62188996 + 139122025 = 7886^2 + 11795^2 .

It is a cyclic number.

It is not a de Polignac number, because 201311021 - 2²⁶ = 134202157 is a prime.

It is a super-2 number, since 2×201311021² = 81052254352124882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201310993 and 201311011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201311029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46976 + ... + 51081.

It is an arithmetic number, because the mean of its divisors is an integer number (50352783).

Almost surely, 2^201311021 is an apocalyptic number.

It is an amenable number.

201311021 is a deficient number, since it is larger than the sum of its proper divisors (100111).

201311021 is an equidigital number, since it uses as much as digits as its factorization.

201311021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100110.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 201311021 is about 14188.4115037590. The cubic root of 201311021 is about 586.0785819129.

Adding to 201311021 its reverse (120113102), we get a palindrome (321424123).

The spelling of 201311021 in words is "two hundred one million, three hundred eleven thousand, twenty-one".