78997949 has 2 divisors, whose sum is σ = 78997950. Its totient is φ = 78997948.

The previous prime is 78997883. The next prime is 78997957. The reversal of 78997949 is 94979987.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78765625 + 232324 = 8875^2 + 482^2 .

It is an emirp because it is prime and its reverse (94979987) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78997949 - 2²⁰ = 77949373 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 78997891 and 78997900.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78997969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39498974 + 39498975.

It is an arithmetic number, because the mean of its divisors is an integer number (39498975).

Almost surely, 2^78997949 is an apocalyptic number.

It is an amenable number.

78997949 is a deficient number, since it is larger than the sum of its proper divisors (1).

78997949 is an equidigital number, since it uses as much as digits as its factorization.

78997949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10287648, while the sum is 62.

The square root of 78997949 is about 8888.0790388025. The cubic root of 78997949 is about 429.0803293736.

The spelling of 78997949 in words is "seventy-eight million, nine hundred ninety-seven thousand, nine hundred forty-nine".