21389619 has 8 divisors (see below), whose sum is σ = 29182912. Its totient is φ = 13928040.

The previous prime is 21389593. The next prime is 21389629. The reversal of 21389619 is 91698312.

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

It is not a de Polignac number, because 21389619 - 2⁸ = 21389363 is a prime.

It is a super-2 number, since 2×21389619² = 915031601930322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21389629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82777 + ... + 83034.

It is an arithmetic number, because the mean of its divisors is an integer number (3647864).

Almost surely, 2^21389619 is an apocalyptic number.

21389619 is a deficient number, since it is larger than the sum of its proper divisors (7793293).

21389619 is a wasteful number, since it uses less digits than its factorization.

21389619 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165857.

The product of its digits is 23328, while the sum is 39.

The square root of 21389619 is about 4624.8912419645. The cubic root of 21389619 is about 277.5882099251.

The spelling of 21389619 in words is "twenty-one million, three hundred eighty-nine thousand, six hundred nineteen".