7218986 has 4 divisors (see below), whose sum is σ = 10828482. Its totient is φ = 3609492.

The previous prime is 7218983. The next prime is 7218997. The reversal of 7218986 is 6898127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6898127 = 41 ⋅168247.

It can be written as a sum of positive squares in only one way, i.e., 6076225 + 1142761 = 2465^2 + 1069^2 .

It is a super-2 number, since 2×7218986² = 104227517736392, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7218983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1804745 + ... + 1804748.

Almost surely, 2^7218986 is an apocalyptic number.

7218986 is a deficient number, since it is larger than the sum of its proper divisors (3609496).

7218986 is a wasteful number, since it uses less digits than its factorization.

7218986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3609495.

The product of its digits is 48384, while the sum is 41.

The square root of 7218986 is about 2686.8170760214. The cubic root of 7218986 is about 193.2674574082.

The spelling of 7218986 in words is "seven million, two hundred eighteen thousand, nine hundred eighty-six".