78736993261 has 2 divisors, whose sum is σ = 78736993262. Its totient is φ = 78736993260.

The previous prime is 78736993249. The next prime is 78736993273. The reversal of 78736993261 is 16239963787.

It is a balanced prime because it is at equal distance from previous prime (78736993249) and next prime (78736993273).

It can be written as a sum of positive squares in only one way, i.e., 59553081225 + 19183912036 = 244035^2 + 138506^2 .

It is an emirp because it is prime and its reverse (16239963787) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78736993261 - 2¹⁹ = 78736468973 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78736993261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78736993061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39368496630 + 39368496631.

It is an arithmetic number, because the mean of its divisors is an integer number (39368496631).

Almost surely, 2^78736993261 is an apocalyptic number.

It is an amenable number.

78736993261 is a deficient number, since it is larger than the sum of its proper divisors (1).

78736993261 is an equidigital number, since it uses as much as digits as its factorization.

78736993261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20575296, while the sum is 61.

The spelling of 78736993261 in words is "seventy-eight billion, seven hundred thirty-six million, nine hundred ninety-three thousand, two hundred sixty-one".