1393721 has 4 divisors (see below), whose sum is σ = 1592832. Its totient is φ = 1194612.

The previous prime is 1393697. The next prime is 1393723. The reversal of 1393721 is 1273931.

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: 1273931 = 19 ⋅67049.

It is a cyclic number.

It is not a de Polignac number, because 1393721 - 2⁶ = 1393657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1393723) 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, 99545 + ... + 99558.

It is an arithmetic number, because the mean of its divisors is an integer number (398208).

2^1393721 is an apocalyptic number.

It is an amenable number.

1393721 is a deficient number, since it is larger than the sum of its proper divisors (199111).

1393721 is an equidigital number, since it uses as much as digits as its factorization.

1393721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199110.

The product of its digits is 1134, while the sum is 26.

The square root of 1393721 is about 1180.5596130649. The cubic root of 1393721 is about 111.7013995567.

The spelling of 1393721 in words is "one million, three hundred ninety-three thousand, seven hundred twenty-one".