2151684 has 60 divisors (see below), whose sum is σ = 5844300. Its totient is φ = 689472.

The previous prime is 2151683. The next prime is 2151701. The reversal of 2151684 is 4861512.

It can be written as a sum of positive squares in 2 ways, for example, as 1633284 + 518400 = 1278^2 + 720^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2151683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 9282 + ... + 9510.

It is an arithmetic number, because the mean of its divisors is an integer number (97405).

2^2151684 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2151684, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2922150).

2151684 is an abundant number, since it is smaller than the sum of its proper divisors (3692616).

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

2151684 is a wasteful number, since it uses less digits than its factorization.

2151684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274 (or 263 counting only the distinct ones).

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

The square root of 2151684 is about 1466.8619566953. The cubic root of 2151684 is about 129.0999765802.

The spelling of 2151684 in words is "two million, one hundred fifty-one thousand, six hundred eighty-four".