78477389 has 4 divisors (see below), whose sum is σ = 83093724. Its totient is φ = 73861056.

The previous prime is 78477379. The next prime is 78477397. The reversal of 78477389 is 98377487.

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 61936900 + 16540489 = 7870^2 + 4067^2 .

It is not a de Polignac number, because 78477389 - 2¹² = 78473293 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 78477389.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78477319) 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, 2308142 + ... + 2308175.

It is an arithmetic number, because the mean of its divisors is an integer number (20773431).

Almost surely, 2^78477389 is an apocalyptic number.

It is an amenable number.

78477389 is a deficient number, since it is larger than the sum of its proper divisors (4616335).

78477389 is a wasteful number, since it uses less digits than its factorization.

78477389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4616334.

The product of its digits is 2370816, while the sum is 53.

The square root of 78477389 is about 8858.7464688860. The cubic root of 78477389 is about 428.1357711890.

The spelling of 78477389 in words is "seventy-eight million, four hundred seventy-seven thousand, three hundred eighty-nine".