7978615 has 4 divisors (see below), whose sum is σ = 9574344. Its totient is φ = 6382888.

The previous prime is 7978609. The next prime is 7978637. The reversal of 7978615 is 5168797.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5168797 = 1093 ⋅4729.

It is a cyclic number.

It is not a de Polignac number, because 7978615 - 2¹¹ = 7976567 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 797857 + ... + 797866.

It is an arithmetic number, because the mean of its divisors is an integer number (2393586).

Almost surely, 2^7978615 is an apocalyptic number.

7978615 is a deficient number, since it is larger than the sum of its proper divisors (1595729).

7978615 is a wasteful number, since it uses less digits than its factorization.

7978615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1595728.

The product of its digits is 105840, while the sum is 43.

The square root of 7978615 is about 2824.6442253849. The cubic root of 7978615 is about 199.8216326394.

The spelling of 7978615 in words is "seven million, nine hundred seventy-eight thousand, six hundred fifteen".