7218739394 has 4 divisors (see below), whose sum is σ = 10828109094. Its totient is φ = 3609369696.

The previous prime is 7218739373. The next prime is 7218739417. The reversal of 7218739394 is 4939378127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 4939378127 = 607 ⋅8137361.

It can be written as a sum of positive squares in only one way, i.e., 5276133769 + 1942605625 = 72637^2 + 44075^2 .

It is a super-2 number, since 2×7218739394² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1804684847 + ... + 1804684850.

Almost surely, 2^7218739394 is an apocalyptic number.

7218739394 is a deficient number, since it is larger than the sum of its proper divisors (3609369700).

7218739394 is a wasteful number, since it uses less digits than its factorization.

7218739394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3609369699.

The product of its digits is 2286144, while the sum is 53.

The square root of 7218739394 is about 84963.1649245719. The cubic root of 7218739394 is about 1932.6525666247.

The spelling of 7218739394 in words is "seven billion, two hundred eighteen million, seven hundred thirty-nine thousand, three hundred ninety-four".