641990 has 16 divisors (see below), whose sum is σ = 1183248. Its totient is φ = 250656.

The previous prime is 641981. The next prime is 642011. The reversal of 641990 is 99146.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 317 + ... + 1176.

It is an arithmetic number, because the mean of its divisors is an integer number (73953).

2⁶⁴¹⁹⁹⁰ is an apocalyptic number.

641990 is a deficient number, since it is larger than the sum of its proper divisors (541258).

641990 is a wasteful number, since it uses less digits than its factorization.

641990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1543.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 641990 is about 801.2427846789. The cubic root of 641990 is about 86.2666144567.

Subtracting from 641990 its product of nonzero digits (1944), we obtain a palindrome (640046).

The spelling of 641990 in words is "six hundred forty-one thousand, nine hundred ninety".