1663971 has 8 divisors (see below), whose sum is σ = 2270400. Its totient is φ = 1083432.

The previous prime is 1663967. The next prime is 1663973. The reversal of 1663971 is 1793661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1663971 - 2² = 1663967 is a prime.

1663971 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1663973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6321 + ... + 6578.

It is an arithmetic number, because the mean of its divisors is an integer number (283800).

2^1663971 is an apocalyptic number.

1663971 is a deficient number, since it is larger than the sum of its proper divisors (606429).

1663971 is a wasteful number, since it uses less digits than its factorization.

1663971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12945.

The product of its digits is 6804, while the sum is 33.

The square root of 1663971 is about 1289.9499990310. The cubic root of 1663971 is about 118.4991543318.

The spelling of 1663971 in words is "one million, six hundred sixty-three thousand, nine hundred seventy-one".