21020023129 has 4 divisors (see below), whose sum is σ = 24022883584. Its totient is φ = 18017162676.

The previous prime is 21020023117. The next prime is 21020023147. The reversal of 21020023129 is 92132002012.

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 21020023129 - 2²⁵ = 20986468697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21020023109) 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, 1501430217 + ... + 1501430230.

It is an arithmetic number, because the mean of its divisors is an integer number (6005720896).

Almost surely, 2^21020023129 is an apocalyptic number.

It is an amenable number.

21020023129 is a deficient number, since it is larger than the sum of its proper divisors (3002860455).

21020023129 is an equidigital number, since it uses as much as digits as its factorization.

21020023129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3002860454.

The product of its (nonzero) digits is 432, while the sum is 22.

The spelling of 21020023129 in words is "twenty-one billion, twenty million, twenty-three thousand, one hundred twenty-nine".