21199668 has 96 divisors (see below), whose sum is σ = 61286400. Its totient is φ = 5567616.

The previous prime is 21199643. The next prime is 21199681. The reversal of 21199668 is 86699112.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 58873 + ... + 59231.

It is an arithmetic number, because the mean of its divisors is an integer number (638400).

Almost surely, 2^21199668 is an apocalyptic number.

21199668 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21199668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30643200).

21199668 is an abundant number, since it is smaller than the sum of its proper divisors (40086732).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21199668 is a wasteful number, since it uses less digits than its factorization.

21199668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429 (or 427 counting only the distinct ones).

The product of its digits is 46656, while the sum is 42.

The square root of 21199668 is about 4604.3097202512. The cubic root of 21199668 is about 276.7640559706.

The spelling of 21199668 in words is "twenty-one million, one hundred ninety-nine thousand, six hundred sixty-eight".