1643406 has 8 divisors (see below), whose sum is σ = 3286824. Its totient is φ = 547800.

The previous prime is 1643387. The next prime is 1643423. The reversal of 1643406 is 6043461.

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

1643406 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136945 + ... + 136956.

It is an arithmetic number, because the mean of its divisors is an integer number (410853).

2^1643406 is an apocalyptic number.

1643406 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1643406 is a wasteful number, since it uses less digits than its factorization.

1643406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273906.

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 1643406 is about 1281.9539773330. The cubic root of 1643406 is about 118.0089526866.

Adding to 1643406 its reverse (6043461), we get a palindrome (7686867).

It can be divided in two parts, 164 and 3406, that added together give a triangular number (3570 = T₈₄).

The spelling of 1643406 in words is "one million, six hundred forty-three thousand, four hundred six".