1641999 has 8 divisors (see below), whose sum is σ = 2304640. Its totient is φ = 1037016.

The previous prime is 1641971. The next prime is 1642021. The reversal of 1641999 is 9991461.

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

It is a de Polignac number, because none of the positive numbers 2^k-1641999 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 (1641929) 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, 14347 + ... + 14460.

It is an arithmetic number, because the mean of its divisors is an integer number (288080).

2^1641999 is an apocalyptic number.

1641999 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1641999 is a deficient number, since it is larger than the sum of its proper divisors (662641).

1641999 is a wasteful number, since it uses less digits than its factorization.

1641999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28829.

The product of its digits is 17496, while the sum is 39.

The square root of 1641999 is about 1281.4050881747. The cubic root of 1641999 is about 117.9752653317.

Subtracting from 1641999 its product of digits (17496), we obtain a triangular number (1624503 = T₁₈₀₂).

The spelling of 1641999 in words is "one million, six hundred forty-one thousand, nine hundred ninety-nine".