78198949 has 2 divisors, whose sum is σ = 78198950. Its totient is φ = 78198948.

The previous prime is 78198943. The next prime is 78198961. The reversal of 78198949 is 94989187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71402500 + 6796449 = 8450^2 + 2607^2 .

It is a cyclic number.

It is not a de Polignac number, because 78198949 - 2⁷ = 78198821 is a prime.

It is a super-2 number, since 2×78198949² = 12230151249409202, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78198949.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78198943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39099474 + 39099475.

It is an arithmetic number, because the mean of its divisors is an integer number (39099475).

Almost surely, 2^78198949 is an apocalyptic number.

It is an amenable number.

78198949 is a deficient number, since it is larger than the sum of its proper divisors (1).

78198949 is an equidigital number, since it uses as much as digits as its factorization.

78198949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 55.

The square root of 78198949 is about 8843.0169625530. The cubic root of 78198949 is about 427.6288252131.

The spelling of 78198949 in words is "seventy-eight million, one hundred ninety-eight thousand, nine hundred forty-nine".