21939193 has 8 divisors (see below), whose sum is σ = 22239360. Its totient is φ = 21641040.

The previous prime is 21939179. The next prime is 21939233. The reversal of 21939193 is 39193912.

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

It is a cyclic number.

It is not a de Polignac number, because 21939193 - 2⁵ = 21939161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21939133) 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, 46746 + ... + 47212.

It is an arithmetic number, because the mean of its divisors is an integer number (2779920).

Almost surely, 2^21939193 is an apocalyptic number.

It is an amenable number.

21939193 is a deficient number, since it is larger than the sum of its proper divisors (300167).

21939193 is a wasteful number, since it uses less digits than its factorization.

21939193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1007.

The product of its digits is 13122, while the sum is 37.

The square root of 21939193 is about 4683.9292266216. The cubic root of 21939193 is about 279.9455378768.

The spelling of 21939193 in words is "twenty-one million, nine hundred thirty-nine thousand, one hundred ninety-three".