78721402369 has 2 divisors, whose sum is σ = 78721402370. Its totient is φ = 78721402368.

The previous prime is 78721402351. The next prime is 78721402411. The reversal of 78721402369 is 96320412787.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46145484225 + 32575918144 = 214815^2 + 180488^2 .

It is a cyclic number.

It is not a de Polignac number, because 78721402369 - 2⁵ = 78721402337 is a prime.

It is a super-2 number, since 2×78721402369² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78721402339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39360701184 + 39360701185.

It is an arithmetic number, because the mean of its divisors is an integer number (39360701185).

Almost surely, 2^78721402369 is an apocalyptic number.

It is an amenable number.

78721402369 is a deficient number, since it is larger than the sum of its proper divisors (1).

78721402369 is an equidigital number, since it uses as much as digits as its factorization.

78721402369 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1016064, while the sum is 49.

The spelling of 78721402369 in words is "seventy-eight billion, seven hundred twenty-one million, four hundred two thousand, three hundred sixty-nine".