7218681 has 4 divisors (see below), whose sum is σ = 9624912. Its totient is φ = 4812452.

The previous prime is 7218677. The next prime is 7218697. The reversal of 7218681 is 1868127.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1868127 = 3 ⋅622709.

It is a cyclic number.

It is not a de Polignac number, because 7218681 - 2² = 7218677 is a prime.

It is a super-2 number, since 2×7218681² = 104218710759522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7218661) 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, 1203111 + ... + 1203116.

It is an arithmetic number, because the mean of its divisors is an integer number (2406228).

Almost surely, 2^7218681 is an apocalyptic number.

It is an amenable number.

7218681 is a deficient number, since it is larger than the sum of its proper divisors (2406231).

7218681 is a wasteful number, since it uses less digits than its factorization.

7218681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2406230.

The product of its digits is 5376, while the sum is 33.

The square root of 7218681 is about 2686.7603168128. The cubic root of 7218681 is about 193.2647355391.

The spelling of 7218681 in words is "seven million, two hundred eighteen thousand, six hundred eighty-one".