21203121331 has 16 divisors (see below), whose sum is σ = 24306186240. Its totient is φ = 18118647360.

The previous prime is 21203121311. The next prime is 21203121347. The reversal of 21203121331 is 13312130212.

It is a cyclic number.

It is not a de Polignac number, because 21203121331 - 2²⁹ = 20666250419 is a prime.

It is a super-2 number, since 2×21203121331² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21203121299 and 21203121308.

It is not an unprimeable number, because it can be changed into a prime (21203121311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4426920 + ... + 4431706.

It is an arithmetic number, because the mean of its divisors is an integer number (1519136640).

Almost surely, 2^21203121331 is an apocalyptic number.

21203121331 is a deficient number, since it is larger than the sum of its proper divisors (3103064909).

21203121331 is a wasteful number, since it uses less digits than its factorization.

21203121331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6594.

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

Adding to 21203121331 its reverse (13312130212), we get a palindrome (34515251543).

The spelling of 21203121331 in words is "twenty-one billion, two hundred three million, one hundred twenty-one thousand, three hundred thirty-one".