21312463 has 2 divisors, whose sum is σ = 21312464. Its totient is φ = 21312462.

The previous prime is 21312461. The next prime is 21312493. The reversal of 21312463 is 36421312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21312463 - 2¹ = 21312461 is a prime.

Together with 21312461, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21312461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656231 + 10656232.

It is an arithmetic number, because the mean of its divisors is an integer number (10656232).

Almost surely, 2^21312463 is an apocalyptic number.

21312463 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312463 is an equidigital number, since it uses as much as digits as its factorization.

21312463 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 22.

The square root of 21312463 is about 4616.5423208284. The cubic root of 21312463 is about 277.2540384755.

Adding to 21312463 its reverse (36421312), we get a palindrome (57733775).

The spelling of 21312463 in words is "twenty-one million, three hundred twelve thousand, four hundred sixty-three".