191012221 has 4 divisors (see below), whose sum is σ = 202248252. Its totient is φ = 179776192.

The previous prime is 191012219. The next prime is 191012249. The reversal of 191012221 is 122210191.

It is a happy number.

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 124768900 + 66243321 = 11170^2 + 8139^2 .

It is a cyclic number.

It is not a de Polignac number, because 191012221 - 2¹ = 191012219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191012201) 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 3 ways as a sum of consecutive naturals, for example, 5617990 + ... + 5618023.

It is an arithmetic number, because the mean of its divisors is an integer number (50562063).

Almost surely, 2^191012221 is an apocalyptic number.

It is an amenable number.

191012221 is a deficient number, since it is larger than the sum of its proper divisors (11236031).

191012221 is a wasteful number, since it uses less digits than its factorization.

191012221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11236030.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 191012221 is about 13820.7170942755. The cubic root of 191012221 is about 575.9088045646.

The spelling of 191012221 in words is "one hundred ninety-one million, twelve thousand, two hundred twenty-one".