21120121001 has 8 divisors (see below), whose sum is σ = 24297131904. Its totient is φ = 17983072800.

The previous prime is 21120120971. The next prime is 21120121007. The reversal of 21120121001 is 10012102112.

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

It is a de Polignac number, because none of the positive numbers 2^k-21120121001 is a prime.

It is a super-5 number, since 5×21120121001⁵ (a number of 53 digits) contains 55555 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21120121007) 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, 9989540 + ... + 9991653.

It is an arithmetic number, because the mean of its divisors is an integer number (3037141488).

Almost surely, 2^21120121001 is an apocalyptic number.

It is an amenable number.

21120121001 is a deficient number, since it is larger than the sum of its proper divisors (3177010903).

21120121001 is a wasteful number, since it uses less digits than its factorization.

21120121001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19981351.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21120121001 its reverse (10012102112), we get a palindrome (31132223113).

The spelling of 21120121001 in words is "twenty-one billion, one hundred twenty million, one hundred twenty-one thousand, one".