2157824 has 18 divisors (see below), whose sum is σ = 4307730. Its totient is φ = 1078784.

The previous prime is 2157823. The next prime is 2157833. The reversal of 2157824 is 4287512.

It can be written as a sum of positive squares in only one way, i.e., 1517824 + 640000 = 1232^2 + 800^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2157821) 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 as a sum of consecutive naturals, namely, 3959 + ... + 4470.

2^2157824 is an apocalyptic number.

It is an amenable number.

2157824 is a deficient number, since it is larger than the sum of its proper divisors (2149906).

2157824 is an frugal number, since it uses more digits than its factorization.

2157824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8445 (or 8431 counting only the distinct ones).

The product of its digits is 4480, while the sum is 29.

The square root of 2157824 is about 1468.9533688991. The cubic root of 2157824 is about 129.2226589480. Note that the first 3 decimals are identical.

The spelling of 2157824 in words is "two million, one hundred fifty-seven thousand, eight hundred twenty-four".