2155640 has 16 divisors (see below), whose sum is σ = 4850280. Its totient is φ = 862240.

The previous prime is 2155639. The next prime is 2155661. The reversal of 2155640 is 465512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26906 + ... + 26985.

2^2155640 is an apocalyptic number.

2155640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2155640 is an abundant number, since it is smaller than the sum of its proper divisors (2694640).

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

2155640 is a wasteful number, since it uses less digits than its factorization.

2155640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53902 (or 53898 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 2155640 is about 1468.2097942733. The cubic root of 2155640 is about 129.1790474894.

The spelling of 2155640 in words is "two million, one hundred fifty-five thousand, six hundred forty".