21312040447 has 2 divisors, whose sum is σ = 21312040448. Its totient is φ = 21312040446.

The previous prime is 21312040411. The next prime is 21312040471. The reversal of 21312040447 is 74404021312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21312040447 - 2¹⁵ = 21312007679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21312040147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656020223 + 10656020224.

It is an arithmetic number, because the mean of its divisors is an integer number (10656020224).

Almost surely, 2^21312040447 is an apocalyptic number.

21312040447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312040447 is an equidigital number, since it uses as much as digits as its factorization.

21312040447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5376, while the sum is 28.

Adding to 21312040447 its reverse (74404021312), we get a palindrome (95716061759).

The spelling of 21312040447 in words is "twenty-one billion, three hundred twelve million, forty thousand, four hundred forty-seven".