78877009 has 4 divisors (see below), whose sum is σ = 78897316. Its totient is φ = 78856704.

The previous prime is 78876949. The next prime is 78877031. The reversal of 78877009 is 90077887.

It is a happy number.

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 60840000 + 18037009 = 7800^2 + 4247^2 .

It is a cyclic number.

It is not a de Polignac number, because 78877009 - 2⁷ = 78876881 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78877009.

It is not an unprimeable number, because it can be changed into a prime (78877069) 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, 2304 + ... + 12769.

It is an arithmetic number, because the mean of its divisors is an integer number (19724329).

Almost surely, 2^78877009 is an apocalyptic number.

It is an amenable number.

78877009 is a deficient number, since it is larger than the sum of its proper divisors (20307).

78877009 is a wasteful number, since it uses less digits than its factorization.

78877009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20306.

The product of its (nonzero) digits is 197568, while the sum is 46.

The square root of 78877009 is about 8881.2729380422. The cubic root of 78877009 is about 428.8612541542.

The spelling of 78877009 in words is "seventy-eight million, eight hundred seventy-seven thousand, nine".