78125405 has 4 divisors (see below), whose sum is σ = 93750492. Its totient is φ = 62500320.

The previous prime is 78125393. The next prime is 78125413. The reversal of 78125405 is 50452187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50452187 = 4409 ⋅11443.

It can be written as a sum of positive squares in 2 ways, for example, as 25664356 + 52461049 = 5066^2 + 7243^2 .

It is not a de Polignac number, because 78125405 - 2²⁶ = 11016541 is a prime.

It is a super-2 number, since 2×78125405² = 12207157812828050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7812536 + ... + 7812545.

It is an arithmetic number, because the mean of its divisors is an integer number (23437623).

Almost surely, 2^78125405 is an apocalyptic number.

It is an amenable number.

78125405 is a deficient number, since it is larger than the sum of its proper divisors (15625087).

78125405 is a wasteful number, since it uses less digits than its factorization.

78125405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15625086.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 78125405 is about 8838.8576750619. The cubic root of 78125405 is about 427.4947253775.

It can be divided in two parts, 78125 and 405, that multiplied together give a 4-th power (31640625 = 75⁴).

The spelling of 78125405 in words is "seventy-eight million, one hundred twenty-five thousand, four hundred five".