2001212191 has 4 divisors (see below), whose sum is σ = 2183140584. Its totient is φ = 1819283800.

The previous prime is 2001212179. The next prime is 2001212197. The reversal of 2001212191 is 1912121002.

It is a happy number.

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 2001212191 - 2¹⁹ = 2000687903 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 (2001212197) 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, 90964180 + ... + 90964201.

It is an arithmetic number, because the mean of its divisors is an integer number (545785146).

Almost surely, 2^2001212191 is an apocalyptic number.

2001212191 is a deficient number, since it is larger than the sum of its proper divisors (181928393).

2001212191 is a wasteful number, since it uses less digits than its factorization.

2001212191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181928392.

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

The square root of 2001212191 is about 44734.9102044477. The cubic root of 2001212191 is about 1260.1755426457.

Adding to 2001212191 its reverse (1912121002), we get a palindrome (3913333193).

The spelling of 2001212191 in words is "two billion, one million, two hundred twelve thousand, one hundred ninety-one".