78405 has 8 divisors (see below), whose sum is σ = 125472. Its totient is φ = 41808.

The previous prime is 78401. The next prime is 78427. The reversal of 78405 is 50487.

78405 = 84² + 85² + ... + 93².

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 78405 - 2² = 78401 is a prime.

It is a super-2 number, since 2×78405² = 12294688050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2599 + ... + 2628.

It is an arithmetic number, because the mean of its divisors is an integer number (15684).

2⁷⁸⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

78405 is a deficient number, since it is larger than the sum of its proper divisors (47067).

78405 is a wasteful number, since it uses less digits than its factorization.

78405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5235.

The product of its (nonzero) digits is 1120, while the sum is 24.

The square root of 78405 is about 280.0089284291. The cubic root of 78405 is about 42.8004090566.

The spelling of 78405 in words is "seventy-eight thousand, four hundred five".