19941221 has 4 divisors (see below), whose sum is σ = 21114252. Its totient is φ = 18768192.

The previous prime is 19941217. The next prime is 19941247. The reversal of 19941221 is 12214991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9084196 + 10857025 = 3014^2 + 3295^2 .

It is a cyclic number.

It is not a de Polignac number, because 19941221 - 2² = 19941217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19941281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 586490 + ... + 586523.

It is an arithmetic number, because the mean of its divisors is an integer number (5278563).

Almost surely, 2^19941221 is an apocalyptic number.

It is an amenable number.

19941221 is a deficient number, since it is larger than the sum of its proper divisors (1173031).

19941221 is a wasteful number, since it uses less digits than its factorization.

19941221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1173030.

The product of its digits is 1296, while the sum is 29.

The square root of 19941221 is about 4465.5594274402. The cubic root of 19941221 is about 271.1755828050.

The spelling of 19941221 in words is "nineteen million, nine hundred forty-one thousand, two hundred twenty-one".