21124231129 has 4 divisors (see below), whose sum is σ = 21125114676. Its totient is φ = 21123347584.

The previous prime is 21124231123. The next prime is 21124231153. The reversal of 21124231129 is 92113242112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8207454025 + 12916777104 = 90595^2 + 113652^2 .

It is a cyclic number.

It is not a de Polignac number, because 21124231129 - 2⁵ = 21124231097 is a prime.

It is a super-2 number, since 2×21124231129² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21124231097 and 21124231106.

It is not an unprimeable number, because it can be changed into a prime (21124231123) 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, 404884 + ... + 454069.

It is an arithmetic number, because the mean of its divisors is an integer number (5281278669).

Almost surely, 2^21124231129 is an apocalyptic number.

It is an amenable number.

21124231129 is a deficient number, since it is larger than the sum of its proper divisors (883547).

21124231129 is an equidigital number, since it uses as much as digits as its factorization.

21124231129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 883546.

The product of its digits is 1728, while the sum is 28.

The spelling of 21124231129 in words is "twenty-one billion, one hundred twenty-four million, two hundred thirty-one thousand, one hundred twenty-nine".