121001100021 has 40 divisors (see below), whose sum is σ = 187628601600. Its totient is φ = 77628818880.

The previous prime is 121001100001. The next prime is 121001100049. The reversal of 121001100021 is 120001100121.

It is a happy number.

It is not a de Polignac number, because 121001100021 - 2⁶ = 121001099957 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 121001099976 and 121001100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121001100001) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 314865 + ... + 584073.

It is an arithmetic number, because the mean of its divisors is an integer number (4690715040).

Almost surely, 2^121001100021 is an apocalyptic number.

It is an amenable number.

121001100021 is a deficient number, since it is larger than the sum of its proper divisors (66627501579).

121001100021 is a wasteful number, since it uses less digits than its factorization.

121001100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269431 (or 269422 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 121001100021 its reverse (120001100121), we get a palindrome (241002200142).

The spelling of 121001100021 in words is "one hundred twenty-one billion, one million, one hundred thousand, twenty-one".