78198985 has 4 divisors (see below), whose sum is σ = 93838788. Its totient is φ = 62559184.

The previous prime is 78198973. The next prime is 78199001. The reversal of 78198985 is 58989187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58989187 = 31 ⋅1902877.

It can be written as a sum of positive squares in 2 ways, for example, as 10086976 + 68112009 = 3176^2 + 8253^2 .

It is a cyclic number.

It is not a de Polignac number, because 78198985 - 2⁹ = 78198473 is a prime.

It is a super-2 number, since 2×78198985² = 12230162510060450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7819894 + ... + 7819903.

It is an arithmetic number, because the mean of its divisors is an integer number (23459697).

Almost surely, 2^78198985 is an apocalyptic number.

It is an amenable number.

78198985 is a deficient number, since it is larger than the sum of its proper divisors (15639803).

78198985 is a wasteful number, since it uses less digits than its factorization.

78198985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15639802.

The product of its digits is 1451520, while the sum is 55.

The square root of 78198985 is about 8843.0189980572. The cubic root of 78198985 is about 427.6288908348.

The spelling of 78198985 in words is "seventy-eight million, one hundred ninety-eight thousand, nine hundred eighty-five".