78147977 has 2 divisors, whose sum is σ = 78147978. Its totient is φ = 78147976.

The previous prime is 78147947. The next prime is 78147989. The reversal of 78147977 is 77974187.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70879561 + 7268416 = 8419^2 + 2696^2 .

It is an emirp because it is prime and its reverse (77974187) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78147977 - 2⁶ = 78147913 is a prime.

It is a super-2 number, since 2×78147977² = 12214212618385058, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78147907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39073988 + 39073989.

It is an arithmetic number, because the mean of its divisors is an integer number (39073989).

Almost surely, 2^78147977 is an apocalyptic number.

It is an amenable number.

78147977 is a deficient number, since it is larger than the sum of its proper divisors (1).

78147977 is an equidigital number, since it uses as much as digits as its factorization.

78147977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 691488, while the sum is 50.

The square root of 78147977 is about 8840.1344446790. The cubic root of 78147977 is about 427.5358920197.

The spelling of 78147977 in words is "seventy-eight million, one hundred forty-seven thousand, nine hundred seventy-seven".