202121100021 has 8 divisors (see below), whose sum is σ = 276778443424. Its totient is φ = 131105578320.

The previous prime is 202121100011. The next prime is 202121100053. The reversal of 202121100021 is 120001121202.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 202121100021 - 2⁷ = 202121099893 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 (202121100011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 910455295 + ... + 910455516.

It is an arithmetic number, because the mean of its divisors is an integer number (34597305428).

Almost surely, 2^202121100021 is an apocalyptic number.

It is an amenable number.

202121100021 is a deficient number, since it is larger than the sum of its proper divisors (74657343403).

202121100021 is a wasteful number, since it uses less digits than its factorization.

202121100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1820910851.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 202121100021 its reverse (120001121202), we get a palindrome (322122221223).

The spelling of 202121100021 in words is "two hundred two billion, one hundred twenty-one million, one hundred thousand, twenty-one".