78969661 has 4 divisors (see below), whose sum is σ = 79054524. Its totient is φ = 78884800.

The previous prime is 78969659. The next prime is 78969689. The reversal of 78969661 is 16696987.

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 66928761 + 12040900 = 8181^2 + 3470^2 .

It is a cyclic number.

It is not a de Polignac number, because 78969661 - 2¹ = 78969659 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78969599 and 78969608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78969601) 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, 41020 + ... + 42901.

It is an arithmetic number, because the mean of its divisors is an integer number (19763631).

Almost surely, 2^78969661 is an apocalyptic number.

It is an amenable number.

78969661 is a deficient number, since it is larger than the sum of its proper divisors (84863).

78969661 is an equidigital number, since it uses as much as digits as its factorization.

78969661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84862.

The product of its digits is 979776, while the sum is 52.

The square root of 78969661 is about 8886.4875513332. The cubic root of 78969661 is about 429.0291074807.

The spelling of 78969661 in words is "seventy-eight million, nine hundred sixty-nine thousand, six hundred sixty-one".