1211022191 has 4 divisors (see below), whose sum is σ = 1222779792. Its totient is φ = 1199264592.

The previous prime is 1211022181. The next prime is 1211022193. The reversal of 1211022191 is 1912201121.

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

It is a cyclic number.

It is not a de Polignac number, because 1211022191 - 2¹⁰ = 1211021167 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 (1211022193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5878646 + ... + 5878851.

It is an arithmetic number, because the mean of its divisors is an integer number (305694948).

Almost surely, 2^1211022191 is an apocalyptic number.

1211022191 is a deficient number, since it is larger than the sum of its proper divisors (11757601).

1211022191 is a wasteful number, since it uses less digits than its factorization.

1211022191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11757600.

The product of its (nonzero) digits is 72, while the sum is 20.

The square root of 1211022191 is about 34799.7441226225. The cubic root of 1211022191 is about 1065.9022209078.

The spelling of 1211022191 in words is "one billion, two hundred eleven million, twenty-two thousand, one hundred ninety-one".