1648639 has 4 divisors (see below), whose sum is σ = 1656256. Its totient is φ = 1641024.

The previous prime is 1648613. The next prime is 1648697. The reversal of 1648639 is 9368461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9368461 = 139 ⋅67399.

It is a cyclic number.

It is not a de Polignac number, because 1648639 - 2¹³ = 1640447 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1648598 and 1648607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1648039) 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, 3474 + ... + 3919.

It is an arithmetic number, because the mean of its divisors is an integer number (414064).

2^1648639 is an apocalyptic number.

1648639 is a deficient number, since it is larger than the sum of its proper divisors (7617).

1648639 is an equidigital number, since it uses as much as digits as its factorization.

1648639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7616.

The product of its digits is 31104, while the sum is 37.

The square root of 1648639 is about 1283.9933800452. The cubic root of 1648639 is about 118.1340762695.

The spelling of 1648639 in words is "one million, six hundred forty-eight thousand, six hundred thirty-nine".