2161540 has 48 divisors (see below), whose sum is σ = 4902912. Its totient is φ = 798336.

The previous prime is 2161513. The next prime is 2161553. The reversal of 2161540 is 451612.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16957 + ... + 17083.

It is an arithmetic number, because the mean of its divisors is an integer number (102144).

2^2161540 is an apocalyptic number.

2161540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2161540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2451456).

2161540 is an abundant number, since it is smaller than the sum of its proper divisors (2741372).

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

2161540 is a wasteful number, since it uses less digits than its factorization.

2161540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196 (or 194 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 2161540 is about 1470.2176709590. The cubic root of 2161540 is about 129.2967947467.

It can be divided in two parts, 2161 and 540, that added together give a triangular number (2701 = T₇₃).

The spelling of 2161540 in words is "two million, one hundred sixty-one thousand, five hundred forty".