21203031311 has 16 divisors (see below), whose sum is σ = 26438138880. Its totient is φ = 16519848480.

The previous prime is 21203031299. The next prime is 21203031341. The reversal of 21203031311 is 11313030212.

It is a cyclic number.

It is not a de Polignac number, because 21203031311 - 2¹⁰ = 21203030287 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 21203031311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203031341) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1202225 + ... + 1219733.

It is an arithmetic number, because the mean of its divisors is an integer number (1652383680).

Almost surely, 2^21203031311 is an apocalyptic number.

21203031311 is a deficient number, since it is larger than the sum of its proper divisors (5235107569).

21203031311 is a wasteful number, since it uses less digits than its factorization.

21203031311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33254.

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 21203031311 its reverse (11313030212), we get a palindrome (32516061523).

The spelling of 21203031311 in words is "twenty-one billion, two hundred three million, thirty-one thousand, three hundred eleven".