7218949 has 4 divisors (see below), whose sum is σ = 7224364. Its totient is φ = 7213536.

The previous prime is 7218947. The next prime is 7218973. The reversal of 7218949 is 9498127.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9498127 = 61 ⋅155707.

It can be written as a sum of positive squares in 2 ways, for example, as 4601025 + 2617924 = 2145^2 + 1618^2 .

It is a cyclic number.

It is not a de Polignac number, because 7218949 - 2¹ = 7218947 is a prime.

It is a super-2 number, since 2×7218949² = 104226449329202, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7218947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 859 + ... + 3895.

It is an arithmetic number, because the mean of its divisors is an integer number (1806091).

Almost surely, 2^7218949 is an apocalyptic number.

It is an amenable number.

7218949 is a deficient number, since it is larger than the sum of its proper divisors (5415).

7218949 is a wasteful number, since it uses less digits than its factorization.

7218949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5414.

The product of its digits is 36288, while the sum is 40.

The square root of 7218949 is about 2686.8101905419. The cubic root of 7218949 is about 193.2671272183.

The spelling of 7218949 in words is "seven million, two hundred eighteen thousand, nine hundred forty-nine".