78140681 has 2 divisors, whose sum is σ = 78140682. Its totient is φ = 78140680.

The previous prime is 78140669. The next prime is 78140701. The reversal of 78140681 is 18604187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62805625 + 15335056 = 7925^2 + 3916^2 .

It is a cyclic number.

It is not a de Polignac number, because 78140681 - 2⁶ = 78140617 is a prime.

It is a super-2 number, since 2×78140681² = 12211932054287522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78140651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39070340 + 39070341.

It is an arithmetic number, because the mean of its divisors is an integer number (39070341).

Almost surely, 2^78140681 is an apocalyptic number.

It is an amenable number.

78140681 is a deficient number, since it is larger than the sum of its proper divisors (1).

78140681 is an equidigital number, since it uses as much as digits as its factorization.

78140681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10752, while the sum is 35.

The square root of 78140681 is about 8839.7217716396. The cubic root of 78140681 is about 427.5225864974.

The spelling of 78140681 in words is "seventy-eight million, one hundred forty thousand, six hundred eighty-one".