21199969 has 8 divisors (see below), whose sum is σ = 25653888. Its totient is φ = 17102400.

The previous prime is 21199949. The next prime is 21199973. The reversal of 21199969 is 96999112.

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

It is not a de Polignac number, because 21199969 - 2⁹ = 21199457 is a prime.

It is a super-2 number, since 2×21199969² = 898877371201922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21199909) 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, 88957 + ... + 89194.

It is an arithmetic number, because the mean of its divisors is an integer number (3206736).

Almost surely, 2^21199969 is an apocalyptic number.

It is an amenable number.

21199969 is a deficient number, since it is larger than the sum of its proper divisors (4453919).

21199969 is a wasteful number, since it uses less digits than its factorization.

21199969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178175.

The product of its digits is 78732, while the sum is 46.

The square root of 21199969 is about 4604.3424069024. The cubic root of 21199969 is about 276.7653658274.

The spelling of 21199969 in words is "twenty-one million, one hundred ninety-nine thousand, nine hundred sixty-nine".