21005412431 has 2 divisors, whose sum is σ = 21005412432. Its totient is φ = 21005412430.

The previous prime is 21005412383. The next prime is 21005412433. The reversal of 21005412431 is 13421450012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21005412431 - 2³⁴ = 3825543247 is a prime.

It is a super-2 number, since 2×21005412431² (a number of 21 digits) contains 22 as substring.

Together with 21005412433, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21005412397 and 21005412406.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21005412433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502706215 + 10502706216.

It is an arithmetic number, because the mean of its divisors is an integer number (10502706216).

Almost surely, 2^21005412431 is an apocalyptic number.

21005412431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21005412431 is an equidigital number, since it uses as much as digits as its factorization.

21005412431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 21005412431 its reverse (13421450012), we get a palindrome (34426862443).

The spelling of 21005412431 in words is "twenty-one billion, five million, four hundred twelve thousand, four hundred thirty-one".