21093819 has 8 divisors (see below), whose sum is σ = 29605440. Its totient is φ = 13322376.

The previous prime is 21093799. The next prime is 21093833. The reversal of 21093819 is 91839012.

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

It is not a de Polignac number, because 21093819 - 2⁸ = 21093563 is a prime.

It is a super-2 number, since 2×21093819² = 889898400009522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21093819.

It is not an unprimeable number, because it can be changed into a prime (21093899) 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, 184977 + ... + 185090.

It is an arithmetic number, because the mean of its divisors is an integer number (3700680).

Almost surely, 2^21093819 is an apocalyptic number.

21093819 is a deficient number, since it is larger than the sum of its proper divisors (8511621).

21093819 is a wasteful number, since it uses less digits than its factorization.

21093819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370089.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 21093819 is about 4592.8007794809. The cubic root of 21093819 is about 276.3026636696.

It can be divided in two parts, 21093 and 819, that added together give a palindrome (21912).

The spelling of 21093819 in words is "twenty-one million, ninety-three thousand, eight hundred nineteen".