7138978961 has 2 divisors, whose sum is σ = 7138978962. Its totient is φ = 7138978960.

The previous prime is 7138978919. The next prime is 7138978967. The reversal of 7138978961 is 1698798317.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6665089600 + 473889361 = 81640^2 + 21769^2 .

It is an emirp because it is prime and its reverse (1698798317) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7138978961 is a prime.

It is a super-3 number, since 3×7138978961³ (a number of 31 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 7138978961.

It is not a weakly prime, because it can be changed into another prime (7138978967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3569489480 + 3569489481.

It is an arithmetic number, because the mean of its divisors is an integer number (3569489481).

Almost surely, 2^7138978961 is an apocalyptic number.

It is an amenable number.

7138978961 is a deficient number, since it is larger than the sum of its proper divisors (1).

7138978961 is an equidigital number, since it uses as much as digits as its factorization.

7138978961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4572288, while the sum is 59.

The square root of 7138978961 is about 84492.4787244403. The cubic root of 7138978961 is about 1925.5081773887.

The spelling of 7138978961 in words is "seven billion, one hundred thirty-eight million, nine hundred seventy-eight thousand, nine hundred sixty-one".