1383721 has 4 divisors (see below), whose sum is σ = 1387152. Its totient is φ = 1380292.

The previous prime is 1383691. The next prime is 1383731. The reversal of 1383721 is 1273831.

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: 1273831 = 13 ⋅97987.

It is a cyclic number.

It is not a de Polignac number, because 1383721 - 2⁷ = 1383593 is a prime.

It is a Duffinian number.

1383721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1383731) 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, 1015 + ... + 1948.

It is an arithmetic number, because the mean of its divisors is an integer number (346788).

2^1383721 is an apocalyptic number.

It is an amenable number.

1383721 is a deficient number, since it is larger than the sum of its proper divisors (3431).

1383721 is an equidigital number, since it uses as much as digits as its factorization.

1383721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3430.

The product of its digits is 1008, while the sum is 25.

The square root of 1383721 is about 1176.3167090542. The cubic root of 1383721 is about 111.4336041526.

The spelling of 1383721 in words is "one million, three hundred eighty-three thousand, seven hundred twenty-one".