7691816209 has 81 divisors (see below), whose sum is σ = 10605811419. Its totient is φ = 5556862080.

The previous prime is 7691816203. The next prime is 7691816213. The reversal of 7691816209 is 9026181967.

The square root of 7691816209 is 87703.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 5988438225 + 1703377984 = 77385^2 + 41272^2 .

It is not a de Polignac number, because 7691816209 - 2¹³ = 7691808017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (7691816203) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 114803194 + ... + 114803260.

Almost surely, 2^7691816209 is an apocalyptic number.

7691816209 is the 87703-rd square number.

7691816209 is the 43852-nd centered octagonal number.

It is an amenable number.

7691816209 is a deficient number, since it is larger than the sum of its proper divisors (2913995210).

7691816209 is a wasteful number, since it uses less digits than its factorization.

7691816209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204 (or 102 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 49.

The cubic root of 7691816209 is about 1973.9809908804.

Multiplying 7691816209 by its sum of digits (49), we get a square (376898994241 = 613921²).

7691816209 divided by its sum of digits (49) gives a square (156975841 = 12529²).

The spelling of 7691816209 in words is "seven billion, six hundred ninety-one million, eight hundred sixteen thousand, two hundred nine".