21402143121 has 4 divisors (see below), whose sum is σ = 28536190832. Its totient is φ = 14268095412.

The previous prime is 21402143089. The next prime is 21402143123. The reversal of 21402143121 is 12134120412.

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 not a de Polignac number, because 21402143121 - 2⁵ = 21402143089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21402143123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3567023851 + ... + 3567023856.

It is an arithmetic number, because the mean of its divisors is an integer number (7134047708).

Almost surely, 2^21402143121 is an apocalyptic number.

It is an amenable number.

21402143121 is a deficient number, since it is larger than the sum of its proper divisors (7134047711).

21402143121 is an equidigital number, since it uses as much as digits as its factorization.

21402143121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7134047710.

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 21402143121 its reverse (12134120412), we get a palindrome (33536263533).

The spelling of 21402143121 in words is "twenty-one billion, four hundred two million, one hundred forty-three thousand, one hundred twenty-one".