21043203131 has 4 divisors (see below), whose sum is σ = 21532579992. Its totient is φ = 20553826272.

The previous prime is 21043203127. The next prime is 21043203173. The reversal of 21043203131 is 13130234012.

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 21043203131 - 2² = 21043203127 is a prime.

It is a super-2 number, since 2×21043203131² (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 (21043203101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 244688366 + ... + 244688451.

It is an arithmetic number, because the mean of its divisors is an integer number (5383144998).

Almost surely, 2^21043203131 is an apocalyptic number.

21043203131 is a deficient number, since it is larger than the sum of its proper divisors (489376861).

21043203131 is an equidigital number, since it uses as much as digits as its factorization.

21043203131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 489376860.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21043203131 its reverse (13130234012), we get a palindrome (34173437143).

The spelling of 21043203131 in words is "twenty-one billion, forty-three million, two hundred three thousand, one hundred thirty-one".