21990194 has 8 divisors (see below), whose sum is σ = 33043248. Its totient is φ = 10975780.

The previous prime is 21990193. The next prime is 21990257. The reversal of 21990194 is 49109912.

21990194 is nontrivially palindromic in base 14.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21990193) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 8192 + ... + 10539.

It is an arithmetic number, because the mean of its divisors is an integer number (4130406).

Almost surely, 2^21990194 is an apocalyptic number.

21990194 is a deficient number, since it is larger than the sum of its proper divisors (11053054).

21990194 is a wasteful number, since it uses less digits than its factorization.

21990194 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19320.

The product of its (nonzero) digits is 5832, while the sum is 35.

The square root of 21990194 is about 4689.3703202029. The cubic root of 21990194 is about 280.1622953669.

The spelling of 21990194 in words is "twenty-one million, nine hundred ninety thousand, one hundred ninety-four".