21639194 has 8 divisors (see below), whose sum is σ = 33009120. Its totient is φ = 10636156.

The previous prime is 21639151. The next prime is 21639199. The reversal of 21639194 is 49193612.

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

It is not an unprimeable number, because it can be changed into a prime (21639199) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 91574 + ... + 91809.

It is an arithmetic number, because the mean of its divisors is an integer number (4126140).

Almost surely, 2^21639194 is an apocalyptic number.

21639194 is a deficient number, since it is larger than the sum of its proper divisors (11369926).

21639194 is a wasteful number, since it uses less digits than its factorization.

21639194 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183444.

The product of its digits is 11664, while the sum is 35.

The square root of 21639194 is about 4651.7947074221. The cubic root of 21639194 is about 278.6636749321.

The spelling of 21639194 in words is "twenty-one million, six hundred thirty-nine thousand, one hundred ninety-four".