21366419 has 4 divisors (see below), whose sum is σ = 21636960. Its totient is φ = 21095880.

The previous prime is 21366407. The next prime is 21366463. The reversal of 21366419 is 91466312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21366419 - 2⁴ = 21366403 is a prime.

It is a super-2 number, since 2×21366419² = 913047721767122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21366619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135152 + ... + 135309.

It is an arithmetic number, because the mean of its divisors is an integer number (5409240).

Almost surely, 2^21366419 is an apocalyptic number.

21366419 is a deficient number, since it is larger than the sum of its proper divisors (270541).

21366419 is an equidigital number, since it uses as much as digits as its factorization.

21366419 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270540.

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

The square root of 21366419 is about 4622.3823943936. The cubic root of 21366419 is about 277.4878126834.

The spelling of 21366419 in words is "twenty-one million, three hundred sixty-six thousand, four hundred nineteen".