7791121381 has 2 divisors, whose sum is σ = 7791121382. Its totient is φ = 7791121380.

The previous prime is 7791121249. The next prime is 7791121441. The reversal of 7791121381 is 1831211977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7777652481 + 13468900 = 88191^2 + 3670^2 .

It is a cyclic number.

It is not a de Polignac number, because 7791121381 - 2¹⁷ = 7790990309 is a prime.

It is a super-2 number, since 2×7791121381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7791121081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3895560690 + 3895560691.

It is an arithmetic number, because the mean of its divisors is an integer number (3895560691).

Almost surely, 2^7791121381 is an apocalyptic number.

It is an amenable number.

7791121381 is a deficient number, since it is larger than the sum of its proper divisors (1).

7791121381 is an equidigital number, since it uses as much as digits as its factorization.

7791121381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 40.

The square root of 7791121381 is about 88267.3290691409. The cubic root of 7791121381 is about 1982.4397179090.

The spelling of 7791121381 in words is "seven billion, seven hundred ninety-one million, one hundred twenty-one thousand, three hundred eighty-one".