21819463 has 2 divisors, whose sum is σ = 21819464. Its totient is φ = 21819462.

The previous prime is 21819461. The next prime is 21819521. The reversal of 21819463 is 36491812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21819463 - 2¹ = 21819461 is a prime.

Together with 21819461, 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 (21819461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10909731 + 10909732.

It is an arithmetic number, because the mean of its divisors is an integer number (10909732).

Almost surely, 2^21819463 is an apocalyptic number.

21819463 is a deficient number, since it is larger than the sum of its proper divisors (1).

21819463 is an equidigital number, since it uses as much as digits as its factorization.

21819463 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 34.

The square root of 21819463 is about 4671.1308052762. The cubic root of 21819463 is about 279.4353544531.

The spelling of 21819463 in words is "twenty-one million, eight hundred nineteen thousand, four hundred sixty-three".