7218742191 has 4 divisors (see below), whose sum is σ = 9624989592. Its totient is φ = 4812494792.

The previous prime is 7218742171. The next prime is 7218742247. The reversal of 7218742191 is 1912478127.

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 7218742191 - 2⁹ = 7218741679 is a prime.

It is a super-2 number, since 2×7218742191² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7218742171) 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, 1203123696 + ... + 1203123701.

It is an arithmetic number, because the mean of its divisors is an integer number (2406247398).

Almost surely, 2^7218742191 is an apocalyptic number.

7218742191 is a deficient number, since it is larger than the sum of its proper divisors (2406247401).

7218742191 is a wasteful number, since it uses less digits than its factorization.

7218742191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2406247400.

The product of its digits is 56448, while the sum is 42.

The square root of 7218742191 is about 84963.1813846445. The cubic root of 7218742191 is about 1932.6528162356.

The spelling of 7218742191 in words is "seven billion, two hundred eighteen million, seven hundred forty-two thousand, one hundred ninety-one".