21432144431 has 4 divisors (see below), whose sum is σ = 21888147552. Its totient is φ = 20976141312.

The previous prime is 21432144403. The next prime is 21432144449. The reversal of 21432144431 is 13444123412.

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 21432144431 - 2¹⁰ = 21432143407 is a prime.

It is a super-2 number, since 2×21432144431² (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 = 21432144394 and 21432144403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21432144401) 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, 228001490 + ... + 228001583.

It is an arithmetic number, because the mean of its divisors is an integer number (5472036888).

Almost surely, 2^21432144431 is an apocalyptic number.

21432144431 is a deficient number, since it is larger than the sum of its proper divisors (456003121).

21432144431 is an equidigital number, since it uses as much as digits as its factorization.

21432144431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456003120.

The product of its digits is 9216, while the sum is 29.

Adding to 21432144431 its reverse (13444123412), we get a palindrome (34876267843).

The spelling of 21432144431 in words is "twenty-one billion, four hundred thirty-two million, one hundred forty-four thousand, four hundred thirty-one".