21974199 has 16 divisors (see below), whose sum is σ = 32642400. Its totient is φ = 13055616.

The previous prime is 21974179. The next prime is 21974201. The reversal of 21974199 is 99147912.

It is not a de Polignac number, because 21974199 - 2⁹ = 21973687 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21974199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21974119) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8584 + ... + 10845.

It is an arithmetic number, because the mean of its divisors is an integer number (2040150).

Almost surely, 2^21974199 is an apocalyptic number.

21974199 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21974199 is a deficient number, since it is larger than the sum of its proper divisors (10668201).

21974199 is a wasteful number, since it uses less digits than its factorization.

21974199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19474.

The product of its digits is 40824, while the sum is 42.

The square root of 21974199 is about 4687.6645571116. The cubic root of 21974199 is about 280.0943517061.

The spelling of 21974199 in words is "twenty-one million, nine hundred seventy-four thousand, one hundred ninety-nine".