1640191 has 8 divisors (see below), whose sum is σ = 1910304. Its totient is φ = 1379040.

The previous prime is 1640189. The next prime is 1640201. The reversal of 1640191 is 1910461.

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

It is a cyclic number.

It is not a de Polignac number, because 1640191 - 2¹ = 1640189 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 (1640131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1840 + ... + 2581.

It is an arithmetic number, because the mean of its divisors is an integer number (238788).

2^1640191 is an apocalyptic number.

1640191 is a deficient number, since it is larger than the sum of its proper divisors (270113).

1640191 is an equidigital number, since it uses as much as digits as its factorization.

1640191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4481.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 1640191 is about 1280.6994182867. The cubic root of 1640191 is about 117.9319486965.

The spelling of 1640191 in words is "one million, six hundred forty thousand, one hundred ninety-one".