2157729 has 16 divisors (see below), whose sum is σ = 3378048. Its totient is φ = 1199232.

The previous prime is 2157721. The next prime is 2157731. The reversal of 2157729 is 9277512.

It is not a de Polignac number, because 2157729 - 2³ = 2157721 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2157729.

It is not an unprimeable number, because it can be changed into a prime (2157721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 612 + ... + 2165.

It is an arithmetic number, because the mean of its divisors is an integer number (211128).

2^2157729 is an apocalyptic number.

It is an amenable number.

2157729 is a deficient number, since it is larger than the sum of its proper divisors (1220319).

2157729 is a wasteful number, since it uses less digits than its factorization.

2157729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2824.

The product of its digits is 8820, while the sum is 33.

The square root of 2157729 is about 1468.9210325950. The cubic root of 2157729 is about 129.2207625417.

The spelling of 2157729 in words is "two million, one hundred fifty-seven thousand, seven hundred twenty-nine".