202121312021 has 4 divisors (see below), whose sum is σ = 202142816832. Its totient is φ = 202099807212.

The previous prime is 202121312011. The next prime is 202121312027. The reversal of 202121312021 is 120213121202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 120213121202 = 2 ⋅60106560601.

It is a cyclic number.

It is not a de Polignac number, because 202121312021 - 2³⁴ = 184941442837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (202121312027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10738301 + ... + 10757106.

It is an arithmetic number, because the mean of its divisors is an integer number (50535704208).

Almost surely, 2^202121312021 is an apocalyptic number.

It is an amenable number.

202121312021 is a deficient number, since it is larger than the sum of its proper divisors (21504811).

202121312021 is an equidigital number, since it uses as much as digits as its factorization.

202121312021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21504810.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 202121312021 its reverse (120213121202), we get a palindrome (322334433223).

The spelling of 202121312021 in words is "two hundred two billion, one hundred twenty-one million, three hundred twelve thousand, twenty-one".