1864721 has 4 divisors (see below), whose sum is σ = 1910244. Its totient is φ = 1819200.

The previous prime is 1864711. The next prime is 1864739. The reversal of 1864721 is 1274681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1274681 = 331 ⋅3851.

It can be written as a sum of positive squares in 2 ways, for example, as 55696 + 1809025 = 236^2 + 1345^2 .

It is a cyclic number.

It is not a de Polignac number, because 1864721 - 2⁶ = 1864657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1864711) 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, 22700 + ... + 22781.

It is an arithmetic number, because the mean of its divisors is an integer number (477561).

2^1864721 is an apocalyptic number.

It is an amenable number.

1864721 is a deficient number, since it is larger than the sum of its proper divisors (45523).

1864721 is an equidigital number, since it uses as much as digits as its factorization.

1864721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45522.

The product of its digits is 2688, while the sum is 29.

The square root of 1864721 is about 1365.5478753965. The cubic root of 1864721 is about 123.0848556285.

The spelling of 1864721 in words is "one million, eight hundred sixty-four thousand, seven hundred twenty-one".