78609997 has 4 divisors (see below), whose sum is σ = 80527356. Its totient is φ = 76692640.

The previous prime is 78609983. The next prime is 78610003. The reversal of 78609997 is 79990687.

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 13097161 + 65512836 = 3619^2 + 8094^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78609997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78609197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 958618 + ... + 958699.

It is an arithmetic number, because the mean of its divisors is an integer number (20131839).

Almost surely, 2^78609997 is an apocalyptic number.

It is an amenable number.

78609997 is a deficient number, since it is larger than the sum of its proper divisors (1917359).

78609997 is a wasteful number, since it uses less digits than its factorization.

78609997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1917358.

The product of its (nonzero) digits is 1714608, while the sum is 55.

The square root of 78609997 is about 8866.2278901458. The cubic root of 78609997 is about 428.3767844744.

The spelling of 78609997 in words is "seventy-eight million, six hundred nine thousand, nine hundred ninety-seven".