21142432121 has 4 divisors (see below), whose sum is σ = 21143265792. Its totient is φ = 21141598452.

The previous prime is 21142432079. The next prime is 21142432127. The reversal of 21142432121 is 12123424112.

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 21142432121 - 2²² = 21138237817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21142432127) 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, 377561 + ... + 429926.

It is an arithmetic number, because the mean of its divisors is an integer number (5285816448).

Almost surely, 2^21142432121 is an apocalyptic number.

It is an amenable number.

21142432121 is a deficient number, since it is larger than the sum of its proper divisors (833671).

21142432121 is an equidigital number, since it uses as much as digits as its factorization.

21142432121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 833670.

The product of its digits is 768, while the sum is 23.

Adding to 21142432121 its reverse (12123424112), we get a palindrome (33265856233).

The spelling of 21142432121 in words is "twenty-one billion, one hundred forty-two million, four hundred thirty-two thousand, one hundred twenty-one".