21663419 has 2 divisors, whose sum is σ = 21663420. Its totient is φ = 21663418.

The previous prime is 21663413. The next prime is 21663427. The reversal of 21663419 is 91436612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21663419 - 2⁴ = 21663403 is a prime.

It is a super-2 number, since 2×21663419² = 938607445539122, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21663413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10831709 + 10831710.

It is an arithmetic number, because the mean of its divisors is an integer number (10831710).

Almost surely, 2^21663419 is an apocalyptic number.

21663419 is a deficient number, since it is larger than the sum of its proper divisors (1).

21663419 is an equidigital number, since it uses as much as digits as its factorization.

21663419 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 32.

The square root of 21663419 is about 4654.3978128218. The cubic root of 21663419 is about 278.7676238128.

The spelling of 21663419 in words is "twenty-one million, six hundred sixty-three thousand, four hundred nineteen".