2178864 has 30 divisors (see below), whose sum is σ = 6098196. Its totient is φ = 726240.

The previous prime is 2178829. The next prime is 2178877. The reversal of 2178864 is 4688712.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7422 + ... + 7709.

2^2178864 is an apocalyptic number.

2178864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

2178864 is an abundant number, since it is smaller than the sum of its proper divisors (3919332).

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

2178864 is a wasteful number, since it uses less digits than its factorization.

2178864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15145 (or 15136 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 2178864 is about 1476.0975577515. The cubic root of 2178864 is about 129.6412991379.

Subtracting from 2178864 its sum of digits (36), we obtain a triangular number (2178828 = T₂₀₈₇).

The spelling of 2178864 in words is "two million, one hundred seventy-eight thousand, eight hundred sixty-four".