78379993 has 2 divisors, whose sum is σ = 78379994. Its totient is φ = 78379992.

The previous prime is 78379991. The next prime is 78380009. The reversal of 78379993 is 39997387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78004224 + 375769 = 8832^2 + 613^2 .

It is an emirp because it is prime and its reverse (39997387) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78379993 - 2¹ = 78379991 is a prime.

It is a super-2 number, since 2×78379993² = 12286846605360098, which contains 22 as substring.

Together with 78379991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (78379991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39189996 + 39189997.

It is an arithmetic number, because the mean of its divisors is an integer number (39189997).

Almost surely, 2^78379993 is an apocalyptic number.

It is an amenable number.

78379993 is a deficient number, since it is larger than the sum of its proper divisors (1).

78379993 is an equidigital number, since it uses as much as digits as its factorization.

78379993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2571912, while the sum is 55.

The square root of 78379993 is about 8853.2475962214. The cubic root of 78379993 is about 427.9585822587.

The spelling of 78379993 in words is "seventy-eight million, three hundred seventy-nine thousand, nine hundred ninety-three".