1666631 has 4 divisors (see below), whose sum is σ = 1673232. Its totient is φ = 1660032.

The previous prime is 1666627. The next prime is 1666657. The reversal of 1666631 is 1366661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1666631 - 2² = 1666627 is a prime.

It is a super-2 number, since 2×1666631² = 5555317780322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1666594 and 1666603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666531) 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, 2906 + ... + 3431.

It is an arithmetic number, because the mean of its divisors is an integer number (418308).

2^1666631 is an apocalyptic number.

1666631 is a deficient number, since it is larger than the sum of its proper divisors (6601).

1666631 is an equidigital number, since it uses as much as digits as its factorization.

1666631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6600.

The product of its digits is 3888, while the sum is 29.

The square root of 1666631 is about 1290.9806350213. The cubic root of 1666631 is about 118.5622643934.

The spelling of 1666631 in words is "one million, six hundred sixty-six thousand, six hundred thirty-one".