7217938681 has 4 divisors (see below), whose sum is σ = 7220056932. Its totient is φ = 7215820432.

The previous prime is 7217938669. The next prime is 7217938687. The reversal of 7217938681 is 1868397127.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4876927225 + 2341011456 = 69835^2 + 48384^2 .

It is a cyclic number.

It is not a de Polignac number, because 7217938681 - 2⁵ = 7217938649 is a prime.

It is a super-2 number, since 2×7217938681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7217938687) 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, 1054006 + ... + 1060831.

It is an arithmetic number, because the mean of its divisors is an integer number (1805014233).

Almost surely, 2^7217938681 is an apocalyptic number.

It is an amenable number.

7217938681 is a deficient number, since it is larger than the sum of its proper divisors (2118251).

7217938681 is a wasteful number, since it uses less digits than its factorization.

7217938681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2118250.

The product of its digits is 1016064, while the sum is 52.

The square root of 7217938681 is about 84958.4526754107. The cubic root of 7217938681 is about 1932.5811064444.

The spelling of 7217938681 in words is "seven billion, two hundred seventeen million, nine hundred thirty-eight thousand, six hundred eighty-one".