202121021 has 4 divisors (see below), whose sum is σ = 207050844. Its totient is φ = 197191200.

The previous prime is 202120979. The next prime is 202121053. The reversal of 202121021 is 120121202.

It is a happy number.

202121021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 3705625 + 198415396 = 1925^2 + 14086^2 .

It is a cyclic number.

It is not a de Polignac number, because 202121021 - 2⁶ = 202120957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 202120993 and 202121011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (202121081) 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, 2464850 + ... + 2464931.

It is an arithmetic number, because the mean of its divisors is an integer number (51762711).

Almost surely, 2^202121021 is an apocalyptic number.

It is an amenable number.

202121021 is a deficient number, since it is larger than the sum of its proper divisors (4929823).

202121021 is an equidigital number, since it uses as much as digits as its factorization.

202121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4929822.

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

The square root of 202121021 is about 14216.9272699835. The cubic root of 202121021 is about 586.8635834247.

Adding to 202121021 its reverse (120121202), we get a palindrome (322242223).

The spelling of 202121021 in words is "two hundred two million, one hundred twenty-one thousand, twenty-one".