7778345081 has 4 divisors (see below), whose sum is σ = 8376679332. Its totient is φ = 7180010832.

The previous prime is 7778345051. The next prime is 7778345093. The reversal of 7778345081 is 1805438777.

It is a happy number.

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 1897909225 + 5880435856 = 43565^2 + 76684^2 .

It is a cyclic number.

It is not a de Polignac number, because 7778345081 - 2¹⁴ = 7778328697 is a prime.

It is a super-2 number, since 2×7778345081² (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 (7778345051) 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, 299167106 + ... + 299167131.

It is an arithmetic number, because the mean of its divisors is an integer number (2094169833).

Almost surely, 2^7778345081 is an apocalyptic number.

It is an amenable number.

7778345081 is a deficient number, since it is larger than the sum of its proper divisors (598334251).

7778345081 is a wasteful number, since it uses less digits than its factorization.

7778345081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 598334250.

The product of its (nonzero) digits is 1317120, while the sum is 50.

The square root of 7778345081 is about 88194.9266171246. The cubic root of 7778345081 is about 1981.3554879319.

The spelling of 7778345081 in words is "seven billion, seven hundred seventy-eight million, three hundred forty-five thousand, eighty-one".