2821729 has 4 divisors (see below), whose sum is σ = 2919060. Its totient is φ = 2724400.

The previous prime is 2821717. The next prime is 2821733. The reversal of 2821729 is 9271282.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 490000 + 2331729 = 700^2 + 1527^2 .

It is a cyclic number.

It is not a de Polignac number, because 2821729 - 2⁷ = 2821601 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2821729.

It is not an unprimeable number, because it can be changed into a prime (2821759) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48622 + ... + 48679.

It is an arithmetic number, because the mean of its divisors is an integer number (729765).

2^2821729 is an apocalyptic number.

2821729 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

2821729 is a deficient number, since it is larger than the sum of its proper divisors (97331).

2821729 is an equidigital number, since it uses as much as digits as its factorization.

2821729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97330.

The product of its digits is 4032, while the sum is 31.

The square root of 2821729 is about 1679.8002857483. The cubic root of 2821729 is about 141.3096325858.

Adding to 2821729 its product of digits (4032), we get a 4-th power (2825761 = 41⁴).

It can be divided in two parts, 282 and 1729, that multiplied together give a triangular number (487578 = T₉₈₇).

The spelling of 2821729 in words is "two million, eight hundred twenty-one thousand, seven hundred twenty-nine".