1721487 has 4 divisors (see below), whose sum is σ = 2295320. Its totient is φ = 1147656.

The previous prime is 1721477. The next prime is 1721497. The reversal of 1721487 is 7841271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7841271 = 3 ⋅2613757.

It is an interprime number because it is at equal distance from previous prime (1721477) and next prime (1721497).

It is not a de Polignac number, because 1721487 - 2¹⁴ = 1705103 is a prime.

It is a D-number.

It is a Duffinian number.

1721487 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721407) 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, 286912 + ... + 286917.

It is an arithmetic number, because the mean of its divisors is an integer number (573830).

2^1721487 is an apocalyptic number.

1721487 is a deficient number, since it is larger than the sum of its proper divisors (573833).

1721487 is an equidigital number, since it uses as much as digits as its factorization.

1721487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 573832.

The product of its digits is 3136, while the sum is 30.

The square root of 1721487 is about 1312.0544958194. The cubic root of 1721487 is about 119.8490462989.

The spelling of 1721487 in words is "one million, seven hundred twenty-one thousand, four hundred eighty-seven".