21201000121 has 4 divisors (see below), whose sum is σ = 24229714432. Its totient is φ = 18172285812.

The previous prime is 21201000113. The next prime is 21201000137. The reversal of 21201000121 is 12100010212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21201000121 - 2³ = 21201000113 is a prime.

It is a super-2 number, since 2×21201000121² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21201000098 and 21201000107.

It is not an unprimeable number, because it can be changed into a prime (21201000151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1514357145 + ... + 1514357158.

It is an arithmetic number, because the mean of its divisors is an integer number (6057428608).

Almost surely, 2^21201000121 is an apocalyptic number.

It is an amenable number.

21201000121 is a deficient number, since it is larger than the sum of its proper divisors (3028714311).

21201000121 is an equidigital number, since it uses as much as digits as its factorization.

21201000121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3028714310.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21201000121 its reverse (12100010212), we get a palindrome (33301010333).

The spelling of 21201000121 in words is "twenty-one billion, two hundred one million, one hundred twenty-one", and thus it is an aban number.