191221716 has 72 divisors (see below), whose sum is σ = 521189760. Its totient is φ = 54407808.

The previous prime is 191221711. The next prime is 191221717. The reversal of 191221716 is 617122191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191221711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 183525 + ... + 184563.

Almost surely, 2^191221716 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 191221716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (260594880).

191221716 is an abundant number, since it is smaller than the sum of its proper divisors (329968044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

191221716 is a wasteful number, since it uses less digits than its factorization.

191221716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1373 (or 1364 counting only the distinct ones).

The product of its digits is 1512, while the sum is 30.

The square root of 191221716 is about 13828.2940379499. The cubic root of 191221716 is about 576.1192726577.

The spelling of 191221716 in words is "one hundred ninety-one million, two hundred twenty-one thousand, seven hundred sixteen".