7811248121 has 2 divisors, whose sum is σ = 7811248122. Its totient is φ = 7811248120.

The previous prime is 7811248103. The next prime is 7811248129. The reversal of 7811248121 is 1218421187.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7341919225 + 469328896 = 85685^2 + 21664^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7811248121 is a prime.

It is a super-2 number, since 2×7811248121² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (7811248129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3905624060 + 3905624061.

It is an arithmetic number, because the mean of its divisors is an integer number (3905624061).

Almost surely, 2^7811248121 is an apocalyptic number.

It is an amenable number.

7811248121 is a deficient number, since it is larger than the sum of its proper divisors (1).

7811248121 is an equidigital number, since it uses as much as digits as its factorization.

7811248121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7168, while the sum is 35.

The square root of 7811248121 is about 88381.2656675610. The cubic root of 7811248121 is about 1984.1453234831.

The spelling of 7811248121 in words is "seven billion, eight hundred eleven million, two hundred forty-eight thousand, one hundred twenty-one".