21113133431 has 16 divisors (see below), whose sum is σ = 24108655200. Its totient is φ = 18328508928.

The previous prime is 21113133427. The next prime is 21113133497. The reversal of 21113133431 is 13433131112.

It is a cyclic number.

It is not a de Polignac number, because 21113133431 - 2² = 21113133427 is a prime.

It is a super-4 number, since 4×21113133431⁴ (a number of 42 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21113133397 and 21113133406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21113133931) 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, 278126 + ... + 345803.

It is an arithmetic number, because the mean of its divisors is an integer number (1506790950).

Almost surely, 2^21113133431 is an apocalyptic number.

21113133431 is a deficient number, since it is larger than the sum of its proper divisors (2995521769).

21113133431 is a wasteful number, since it uses less digits than its factorization.

21113133431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 624098.

The product of its digits is 648, while the sum is 23.

Adding to 21113133431 its reverse (13433131112), we get a palindrome (34546264543).

The spelling of 21113133431 in words is "twenty-one billion, one hundred thirteen million, one hundred thirty-three thousand, four hundred thirty-one".