7978740 has 144 divisors (see below), whose sum is σ = 28242816. Its totient is φ = 1647360.

The previous prime is 7978721. The next prime is 7978753. The reversal of 7978740 is 478797.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 7978692 and 7978701.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 50742 + ... + 50898.

Almost surely, 2^7978740 is an apocalyptic number.

7978740 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7978740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14121408).

7978740 is an abundant number, since it is smaller than the sum of its proper divisors (20264076).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

7978740 is a wasteful number, since it uses less digits than its factorization.

7978740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198 (or 185 counting only the distinct ones).

The product of its (nonzero) digits is 98784, while the sum is 42.

The square root of 7978740 is about 2824.6663519786. Note that the first 3 decimals coincide. The cubic root of 7978740 is about 199.8226761611.

The spelling of 7978740 in words is "seven million, nine hundred seventy-eight thousand, seven hundred forty".