10001121021 has 24 divisors (see below), whose sum is σ = 15019315584. Its totient is φ = 6407691840.

The previous prime is 10001121019. The next prime is 10001121059. The reversal of 10001121021 is 12012110001.

It is a happy number.

It is not a de Polignac number, because 10001121021 - 2¹ = 10001121019 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 = 10001120994 and 10001121012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10001121001) 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, 177541 + ... + 226986.

It is an arithmetic number, because the mean of its divisors is an integer number (625804816).

Almost surely, 2^10001121021 is an apocalyptic number.

It is an amenable number.

10001121021 is a deficient number, since it is larger than the sum of its proper divisors (5018194563).

10001121021 is a wasteful number, since it uses less digits than its factorization.

10001121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404641 (or 404638 counting only the distinct ones).

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

Adding to 10001121021 its reverse (12012110001), we get a palindrome (22013231022).

The spelling of 10001121021 in words is "ten billion, one million, one hundred twenty-one thousand, twenty-one".