7791378 has 32 divisors (see below), whose sum is σ = 18192384. Its totient is φ = 2178192.

The previous prime is 7791373. The next prime is 7791379. The reversal of 7791378 is 8731977.

It is a happy number.

7791378 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

7791378 is a nontrivial binomial coefficient, being equal to C(3948, 2).

It is a super-2 number, since 2×7791378² = 121411142277768, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (7791373) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1 + ... + 3947.

It is an arithmetic number, because the mean of its divisors is an integer number (568512).

Almost surely, 2^7791378 is an apocalyptic number.

7791378 is the 3947-th triangular number and also the 1974-th hexagonal number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7791378, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9096192).

7791378 is an abundant number, since it is smaller than the sum of its proper divisors (10401006).

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

7791378 is a wasteful number, since it uses less digits than its factorization.

7791378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4006.

The product of its digits is 74088, while the sum is 42.

The square root of 7791378 is about 2791.3039963429. The cubic root of 7791378 is about 198.2461483116.

The spelling of 7791378 in words is "seven million, seven hundred ninety-one thousand, three hundred seventy-eight".