21213244431 has 24 divisors (see below), whose sum is σ = 32267904240. Its totient is φ = 13392086400.

The previous prime is 21213244427. The next prime is 21213244433. The reversal of 21213244431 is 13444231212.

21213244431 is a `hidden beast` number, since 2 + 1 + 213 + 2 + 4 + 443 + 1 = 666.

It is not a de Polignac number, because 21213244431 - 2² = 21213244427 is a prime.

It is a super-3 number, since 3×21213244431³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 21213244395 and 21213244404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213244433) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 392001 + ... + 442821.

It is an arithmetic number, because the mean of its divisors is an integer number (1344496010).

Almost surely, 2^21213244431 is an apocalyptic number.

21213244431 is a deficient number, since it is larger than the sum of its proper divisors (11054659809).

21213244431 is a wasteful number, since it uses less digits than its factorization.

21213244431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53287 (or 53284 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

Adding to 21213244431 its reverse (13444231212), we get a palindrome (34657475643).

The spelling of 21213244431 in words is "twenty-one billion, two hundred thirteen million, two hundred forty-four thousand, four hundred thirty-one".