7213666 has 4 divisors (see below), whose sum is σ = 10820502. Its totient is φ = 3606832.

The previous prime is 7213639. The next prime is 7213667. The reversal of 7213666 is 6663127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6663127 = 29 ⋅229763.

It can be written as a sum of positive squares in only one way, i.e., 6682225 + 531441 = 2585^2 + 729^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (7213667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1803415 + ... + 1803418.

Almost surely, 2^7213666 is an apocalyptic number.

7213666 is a deficient number, since it is larger than the sum of its proper divisors (3606836).

7213666 is a wasteful number, since it uses less digits than its factorization.

7213666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3606835.

The product of its digits is 9072, while the sum is 31.

The square root of 7213666 is about 2685.8268745398. The cubic root of 7213666 is about 193.2199698733.

The spelling of 7213666 in words is "seven million, two hundred thirteen thousand, six hundred sixty-six".