7211891 has 4 divisors (see below), whose sum is σ = 7223784. Its totient is φ = 7200000.

The previous prime is 7211879. The next prime is 7211899. The reversal of 7211891 is 1981127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1981127 = 83 ⋅23869.

It is a cyclic number.

It is not a de Polignac number, because 7211891 - 2²² = 3017587 is a prime.

It is a super-2 number, since 2×7211891² = 104022743591762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7211899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4985 + ... + 6266.

It is an arithmetic number, because the mean of its divisors is an integer number (1805946).

Almost surely, 2^7211891 is an apocalyptic number.

7211891 is a deficient number, since it is larger than the sum of its proper divisors (11893).

7211891 is a wasteful number, since it uses less digits than its factorization.

7211891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11892.

The product of its digits is 1008, while the sum is 29.

The square root of 7211891 is about 2685.4964159351. The cubic root of 7211891 is about 193.2041206236.

The spelling of 7211891 in words is "seven million, two hundred eleven thousand, eight hundred ninety-one".