19929221 has 8 divisors (see below), whose sum is σ = 21633024. Its totient is φ = 18249840.

The previous prime is 19929209. The next prime is 19929223. The reversal of 19929221 is 12292991.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19929221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19929223) 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, 4385 + ... + 7686.

It is an arithmetic number, because the mean of its divisors is an integer number (2704128).

Almost surely, 2^19929221 is an apocalyptic number.

It is an amenable number.

19929221 is a deficient number, since it is larger than the sum of its proper divisors (1703803).

19929221 is a wasteful number, since it uses less digits than its factorization.

19929221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12211.

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

The square root of 19929221 is about 4464.2156085924. The cubic root of 19929221 is about 271.1211769096.

The spelling of 19929221 in words is "nineteen million, nine hundred twenty-nine thousand, two hundred twenty-one".