7978505 has 4 divisors (see below), whose sum is σ = 9574212. Its totient is φ = 6382800.

The previous prime is 7978471. The next prime is 7978519. The reversal of 7978505 is 5058797.

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 2199289 + 5779216 = 1483^2 + 2404^2 .

It is not a de Polignac number, because 7978505 - 2⁶ = 7978441 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 797846 + ... + 797855.

It is an arithmetic number, because the mean of its divisors is an integer number (2393553).

Almost surely, 2^7978505 is an apocalyptic number.

It is an amenable number.

7978505 is a deficient number, since it is larger than the sum of its proper divisors (1595707).

7978505 is a wasteful number, since it uses less digits than its factorization.

7978505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1595706.

The product of its (nonzero) digits is 88200, while the sum is 41.

The square root of 7978505 is about 2824.6247538390. The cubic root of 7978505 is about 199.8207143313.

The spelling of 7978505 in words is "seven million, nine hundred seventy-eight thousand, five hundred five".