21203211131 has 12 divisors (see below), whose sum is σ = 22030815576. Its totient is φ = 20402570880.

The previous prime is 21203211109. The next prime is 21203211149. The reversal of 21203211131 is 13111230212.

It is not a de Polignac number, because 21203211131 - 2³⁴ = 4023341947 is a prime.

It is a super-2 number, since 2×21203211131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21203211031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36320 + ... + 209106.

It is an arithmetic number, because the mean of its divisors is an integer number (1835901298).

Almost surely, 2^21203211131 is an apocalyptic number.

21203211131 is a deficient number, since it is larger than the sum of its proper divisors (827604445).

21203211131 is an equidigital number, since it uses as much as digits as its factorization.

21203211131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172942 (or 172901 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21203211131 its reverse (13111230212), we get a palindrome (34314441343).

The spelling of 21203211131 in words is "twenty-one billion, two hundred three million, two hundred eleven thousand, one hundred thirty-one".