1828721 has 4 divisors (see below), whose sum is σ = 1887744. Its totient is φ = 1769700.

The previous prime is 1828709. The next prime is 1828727. The reversal of 1828721 is 1278281.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1278281 = 17 ⋅75193.

It is a cyclic number.

It is not a de Polignac number, because 1828721 - 2¹⁰ = 1827697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1828727) 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, 29465 + ... + 29526.

It is an arithmetic number, because the mean of its divisors is an integer number (471936).

2^1828721 is an apocalyptic number.

It is an amenable number.

1828721 is a deficient number, since it is larger than the sum of its proper divisors (59023).

1828721 is an equidigital number, since it uses as much as digits as its factorization.

1828721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59022.

The product of its digits is 1792, while the sum is 29.

The square root of 1828721 is about 1352.3021112163. The cubic root of 1828721 is about 122.2876175597.

The spelling of 1828721 in words is "one million, eight hundred twenty-eight thousand, seven hundred twenty-one".