1663871 has 6 divisors (see below), whose sum is σ = 1829016. Its totient is φ = 1512500.

The previous prime is 1663867. The next prime is 1663873. The reversal of 1663871 is 1783661.

It is not a de Polignac number, because 1663871 - 2² = 1663867 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663873) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6755 + ... + 6996.

It is an arithmetic number, because the mean of its divisors is an integer number (304836).

2^1663871 is an apocalyptic number.

1663871 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1663871 is a deficient number, since it is larger than the sum of its proper divisors (165145).

1663871 is a wasteful number, since it uses less digits than its factorization.

1663871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13773 (or 13762 counting only the distinct ones).

The product of its digits is 6048, while the sum is 32.

The square root of 1663871 is about 1289.9112372563. The cubic root of 1663871 is about 118.4967804617.

The spelling of 1663871 in words is "one million, six hundred sixty-three thousand, eight hundred seventy-one".