2157678 has 40 divisors (see below), whose sum is σ = 5096520. Its totient is φ = 680400.

The previous prime is 2157677. The next prime is 2157679. The reversal of 2157678 is 8767512.

2157678 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (2157677) and next prime (2157679).

It is a d-powerful number, because it can be written as 2²¹ + 1 + 5⁵ + 7² + 6⁵ + 7⁵ + 8⁵ .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2157671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2728 + ... + 3428.

It is an arithmetic number, because the mean of its divisors is an integer number (127413).

2^2157678 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2157678, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2548260).

2157678 is an abundant number, since it is smaller than the sum of its proper divisors (2938842).

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

2157678 is a wasteful number, since it uses less digits than its factorization.

2157678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 734 (or 725 counting only the distinct ones).

The product of its digits is 23520, while the sum is 36.

The square root of 2157678 is about 1468.9036728118. The cubic root of 2157678 is about 129.2197444480.

The spelling of 2157678 in words is "two million, one hundred fifty-seven thousand, six hundred seventy-eight".