7782118121 has 4 divisors (see below), whose sum is σ = 7782298500. Its totient is φ = 7781937744.

The previous prime is 7782118117. The next prime is 7782118151. The reversal of 7782118121 is 1218112877.

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 4281739225 + 3500378896 = 65435^2 + 59164^2 .

It is a cyclic number.

It is not a de Polignac number, because 7782118121 - 2² = 7782118117 is a prime.

It is a super-2 number, since 2×7782118121² (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 (7782118151) 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, 16955 + ... + 125903.

It is an arithmetic number, because the mean of its divisors is an integer number (1945574625).

Almost surely, 2^7782118121 is an apocalyptic number.

It is an amenable number.

7782118121 is a deficient number, since it is larger than the sum of its proper divisors (180379).

7782118121 is a wasteful number, since it uses less digits than its factorization.

7782118121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180378.

The product of its digits is 12544, while the sum is 38.

The square root of 7782118121 is about 88216.3143698488. The cubic root of 7782118121 is about 1981.6758013580.

The spelling of 7782118121 in words is "seven billion, seven hundred eighty-two million, one hundred eighteen thousand, one hundred twenty-one".