1663401 has 4 divisors (see below), whose sum is σ = 2217872. Its totient is φ = 1108932.

The previous prime is 1663397. The next prime is 1663457. The reversal of 1663401 is 1043661.

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: 1043661 = 3 ⋅347887.

It is not a de Polignac number, because 1663401 - 2² = 1663397 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1663481) 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, 277231 + ... + 277236.

It is an arithmetic number, because the mean of its divisors is an integer number (554468).

2^1663401 is an apocalyptic number.

It is an amenable number.

1663401 is a deficient number, since it is larger than the sum of its proper divisors (554471).

1663401 is an equidigital number, since it uses as much as digits as its factorization.

1663401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554470.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 1663401 is about 1289.7290413106. The cubic root of 1663401 is about 118.4856219982.

The spelling of 1663401 in words is "one million, six hundred sixty-three thousand, four hundred one".