21203123313 has 16 divisors (see below), whose sum is σ = 28937047040. Its totient is φ = 13802506704.

The previous prime is 21203123281. The next prime is 21203123323. The reversal of 21203123313 is 31332130212.

It is not a de Polignac number, because 21203123313 - 2⁵ = 21203123281 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21203123313.

It is not an unprimeable number, because it can be changed into a prime (21203123323) 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, 436020 + ... + 482202.

It is an arithmetic number, because the mean of its divisors is an integer number (1808565440).

Almost surely, 2^21203123313 is an apocalyptic number.

It is an amenable number.

21203123313 is a deficient number, since it is larger than the sum of its proper divisors (7733923727).

21203123313 is a wasteful number, since it uses less digits than its factorization.

21203123313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49788.

The product of its (nonzero) digits is 648, while the sum is 21.

Adding to 21203123313 its reverse (31332130212), we get a palindrome (52535253525).

The spelling of 21203123313 in words is "twenty-one billion, two hundred three million, one hundred twenty-three thousand, three hundred thirteen".