21012321331 has 4 divisors (see below), whose sum is σ = 22118233000. Its totient is φ = 19906409664.

The previous prime is 21012321289. The next prime is 21012321371. The reversal of 21012321331 is 13312321012.

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

It is a cyclic number.

It is not a de Polignac number, because 21012321331 - 2¹³ = 21012313139 is a prime.

It is a super-2 number, since 2×21012321331² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 1105911649 = 21012321331 / (2 + 1 + 0 + 1 + 2 + 3 + 2 + 1 + 3 + 3 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21012321299 and 21012321308.

It is not an unprimeable number, because it can be changed into a prime (21012321371) 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, 552955806 + ... + 552955843.

It is an arithmetic number, because the mean of its divisors is an integer number (5529558250).

Almost surely, 2^21012321331 is an apocalyptic number.

21012321331 is a deficient number, since it is larger than the sum of its proper divisors (1105911669).

21012321331 is a wasteful number, since it uses less digits than its factorization.

21012321331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1105911668.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21012321331 its reverse (13312321012), we get a palindrome (34324642343).

The spelling of 21012321331 in words is "twenty-one billion, twelve million, three hundred twenty-one thousand, three hundred thirty-one".