7256389981 has 2 divisors, whose sum is σ = 7256389982. Its totient is φ = 7256389980.

The previous prime is 7256389969. The next prime is 7256390039. The reversal of 7256389981 is 1899836527.

7256389981 = 60234² + 60235².

It is an a-pointer prime, because the next prime (7256390039) can be obtained adding 7256389981 to its sum of digits (58).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3628255225 + 3628134756 = 60235^2 + 60234^2 .

It is an emirp because it is prime and its reverse (1899836527) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7256389981 - 2⁵ = 7256389949 is a prime.

It is a super-2 number, since 2×7256389981² (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 (7256387981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3628194990 + 3628194991.

It is an arithmetic number, because the mean of its divisors is an integer number (3628194991).

Almost surely, 2^7256389981 is an apocalyptic number.

7256389981 is the 60235-th centered square number.

It is an amenable number.

7256389981 is a deficient number, since it is larger than the sum of its proper divisors (1).

7256389981 is an equidigital number, since it uses as much as digits as its factorization.

7256389981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6531840, while the sum is 58.

The square root of 7256389981 is about 85184.4468256970. The cubic root of 7256389981 is about 1936.0067700804.

The spelling of 7256389981 in words is "seven billion, two hundred fifty-six million, three hundred eighty-nine thousand, nine hundred eighty-one".