21445619 has 8 divisors (see below), whose sum is σ = 24454080. Its totient is φ = 18631296.

The previous prime is 21445609. The next prime is 21445643. The reversal of 21445619 is 91654412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21445619 - 2⁴ = 21445603 is a prime.

It is a super-2 number, since 2×21445619² = 919829148586322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21445609) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48299 + ... + 48740.

It is an arithmetic number, because the mean of its divisors is an integer number (3056760).

Almost surely, 2^21445619 is an apocalyptic number.

21445619 is a deficient number, since it is larger than the sum of its proper divisors (3008461).

21445619 is a wasteful number, since it uses less digits than its factorization.

21445619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97069.

The product of its digits is 8640, while the sum is 32.

The square root of 21445619 is about 4630.9414809518. The cubic root of 21445619 is about 277.8302493528.

The spelling of 21445619 in words is "twenty-one million, four hundred forty-five thousand, six hundred nineteen".