21024532121 has 4 divisors (see below), whose sum is σ = 21369196644. Its totient is φ = 20679867600.

The previous prime is 21024532117. The next prime is 21024532157. The reversal of 21024532121 is 12123542012.

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 9562688521 + 11461843600 = 97789^2 + 107060^2 .

It is a cyclic number.

It is not a de Polignac number, because 21024532121 - 2² = 21024532117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21024532171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 172332170 + ... + 172332291.

It is an arithmetic number, because the mean of its divisors is an integer number (5342299161).

Almost surely, 2^21024532121 is an apocalyptic number.

It is an amenable number.

21024532121 is a deficient number, since it is larger than the sum of its proper divisors (344664523).

21024532121 is an equidigital number, since it uses as much as digits as its factorization.

21024532121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344664522.

The product of its (nonzero) digits is 960, while the sum is 23.

The spelling of 21024532121 in words is "twenty-one billion, twenty-four million, five hundred thirty-two thousand, one hundred twenty-one".