2181654 has 36 divisors (see below), whose sum is σ = 4976244. Its totient is φ = 716364.

The previous prime is 2181649. The next prime is 2181659. The reversal of 2181654 is 4561812.

2181654 is a `hidden beast` number, since 2 + 1 + 8 + 1 + 654 = 666.

It is an interprime number because it is at equal distance from previous prime (2181649) and next prime (2181659).

It is a super-2 number, since 2×2181654² = 9519228351432, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181659) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 32529 + ... + 32595.

It is an arithmetic number, because the mean of its divisors is an integer number (138229).

2^2181654 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2181654, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2488122).

2181654 is an abundant number, since it is smaller than the sum of its proper divisors (2794590).

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

2181654 is an frugal number, since it uses more digits than its factorization.

2181654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151 (or 72 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 2181654 is about 1477.0423148983. The cubic root of 2181654 is about 129.6966100631.

The spelling of 2181654 in words is "two million, one hundred eighty-one thousand, six hundred fifty-four".