21199817 has 8 divisors (see below), whose sum is σ = 21889824. Its totient is φ = 20518848.

The previous prime is 21199811. The next prime is 21199831. The reversal of 21199817 is 71899112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21199817 is a prime.

It is a pancake number, because a pancake can be divided into 21199817 parts by 6511 straight cuts.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21199811) 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, 2678 + ... + 7040.

It is an arithmetic number, because the mean of its divisors is an integer number (2736228).

Almost surely, 2^21199817 is an apocalyptic number.

It is an amenable number.

21199817 is a deficient number, since it is larger than the sum of its proper divisors (690007).

21199817 is a wasteful number, since it uses less digits than its factorization.

21199817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4519.

The product of its digits is 9072, while the sum is 38.

The square root of 21199817 is about 4604.3259007155. The cubic root of 21199817 is about 276.7647043730.

The spelling of 21199817 in words is "twenty-one million, one hundred ninety-nine thousand, eight hundred seventeen".