1663642 has 4 divisors (see below), whose sum is σ = 2495466. Its totient is φ = 831820.

The previous prime is 1663619. The next prime is 1663681. The reversal of 1663642 is 2463661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2463661 = 271 ⋅9091.

It can be written as a sum of positive squares in only one way, i.e., 942841 + 720801 = 971^2 + 849^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1663642.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 415909 + ... + 415912.

2^1663642 is an apocalyptic number.

1663642 is a deficient number, since it is larger than the sum of its proper divisors (831824).

1663642 is an equidigital number, since it uses as much as digits as its factorization.

1663642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 831823.

The product of its digits is 5184, while the sum is 28.

The square root of 1663642 is about 1289.8224684041. The cubic root of 1663642 is about 118.4913439409.

The spelling of 1663642 in words is "one million, six hundred sixty-three thousand, six hundred forty-two".