2156840 has 32 divisors (see below), whose sum is σ = 5546880. Its totient is φ = 739392.

The previous prime is 2156839. The next prime is 2156849. The reversal of 2156840 is 486512.

It is not an unprimeable number, because it can be changed into a prime (2156849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3572 + ... + 4131.

It is an arithmetic number, because the mean of its divisors is an integer number (173340).

2^2156840 is an apocalyptic number.

2156840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2156840 is an abundant number, since it is smaller than the sum of its proper divisors (3390040).

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

2156840 is a wasteful number, since it uses less digits than its factorization.

2156840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7721 (or 7717 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 2156840 is about 1468.6183983595. The cubic root of 2156840 is about 129.2030134734.

The spelling of 2156840 in words is "two million, one hundred fifty-six thousand, eight hundred forty".