78806689 has 4 divisors (see below), whose sum is σ = 84868756. Its totient is φ = 72744624.

The previous prime is 78806683. The next prime is 78806729. The reversal of 78806689 is 98660887.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 34810000 + 43996689 = 5900^2 + 6633^2 .

It is a cyclic number.

It is not a de Polignac number, because 78806689 - 2⁷ = 78806561 is a prime.

It is a super-2 number, since 2×78806689² = 12420988462285442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78806683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3031014 + ... + 3031039.

It is an arithmetic number, because the mean of its divisors is an integer number (21217189).

Almost surely, 2^78806689 is an apocalyptic number.

It is an amenable number.

78806689 is a deficient number, since it is larger than the sum of its proper divisors (6062067).

78806689 is a wasteful number, since it uses less digits than its factorization.

78806689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6062066.

The product of its (nonzero) digits is 1161216, while the sum is 52.

The square root of 78806689 is about 8877.3131633395. The cubic root of 78806689 is about 428.7337709151.

The spelling of 78806689 in words is "seventy-eight million, eight hundred six thousand, six hundred eighty-nine".