202121010091 has 24 divisors (see below), whose sum is σ = 273435176672. Its totient is φ = 145381737600.

The previous prime is 202121010061. The next prime is 202121010127. The reversal of 202121010091 is 190010121202.

It is a happy number.

It is not a de Polignac number, because 202121010091 - 2⁹ = 202121009579 is a prime.

It is a super-2 number, since 2×202121010091² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (202121010001) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9167130 + ... + 9189151.

Almost surely, 2^202121010091 is an apocalyptic number.

202121010091 is a deficient number, since it is larger than the sum of its proper divisors (71314166581).

202121010091 is a wasteful number, since it uses less digits than its factorization.

202121010091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18356323 (or 18356312 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 19.

Adding to 202121010091 its reverse (190010121202), we get a palindrome (392131131293).

The spelling of 202121010091 in words is "two hundred two billion, one hundred twenty-one million, ten thousand, ninety-one".