78346966421 has 2 divisors, whose sum is σ = 78346966422. Its totient is φ = 78346966420.

The previous prime is 78346966333. The next prime is 78346966517. The reversal of 78346966421 is 12466964387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77514355396 + 832611025 = 278414^2 + 28855^2 .

It is an emirp because it is prime and its reverse (12466964387) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78346966421 - 2²² = 78342772117 is a prime.

It is a super-2 number, since 2×78346966421² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78346966121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39173483210 + 39173483211.

It is an arithmetic number, because the mean of its divisors is an integer number (39173483211).

Almost surely, 2^78346966421 is an apocalyptic number.

It is an amenable number.

78346966421 is a deficient number, since it is larger than the sum of its proper divisors (1).

78346966421 is an equidigital number, since it uses as much as digits as its factorization.

78346966421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10450944, while the sum is 56.

The spelling of 78346966421 in words is "seventy-eight billion, three hundred forty-six million, nine hundred sixty-six thousand, four hundred twenty-one".