21213343431 has 48 divisors (see below), whose sum is σ = 36253235200. Its totient is φ = 11696892480.

The previous prime is 21213343367. The next prime is 21213343447. The reversal of 21213343431 is 13434331212.

It is a happy number.

21213343431 is a `hidden beast` number, since 212 + 13 + 3 + 4 + 3 + 431 = 666.

It is not a de Polignac number, because 21213343431 - 2⁶ = 21213343367 is a prime.

It is a super-2 number, since 2×21213343431² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21213343395 and 21213343404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213343031) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 666036 + ... + 697158.

Almost surely, 2^21213343431 is an apocalyptic number.

21213343431 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21213343431 is a deficient number, since it is larger than the sum of its proper divisors (15039891769).

21213343431 is a wasteful number, since it uses less digits than its factorization.

21213343431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31516 (or 31513 counting only the distinct ones).

The product of its digits is 5184, while the sum is 27.

Adding to 21213343431 its reverse (13434331212), we get a palindrome (34647674643).

The spelling of 21213343431 in words is "twenty-one billion, two hundred thirteen million, three hundred forty-three thousand, four hundred thirty-one".