21214124431 has 4 divisors (see below), whose sum is σ = 21238042032. Its totient is φ = 21190206832.

The previous prime is 21214124423. The next prime is 21214124443. The reversal of 21214124431 is 13442141212.

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 21214124431 - 2³ = 21214124423 is a prime.

It is a super-2 number, since 2×21214124431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21214124396 and 21214124405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21214124401) 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, 11957470 + ... + 11959243.

It is an arithmetic number, because the mean of its divisors is an integer number (5309510508).

Almost surely, 2^21214124431 is an apocalyptic number.

21214124431 is a deficient number, since it is larger than the sum of its proper divisors (23917601).

21214124431 is an equidigital number, since it uses as much as digits as its factorization.

21214124431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23917600.

The product of its digits is 1536, while the sum is 25.

Adding to 21214124431 its reverse (13442141212), we get a palindrome (34656265643).

The spelling of 21214124431 in words is "twenty-one billion, two hundred fourteen million, one hundred twenty-four thousand, four hundred thirty-one".