641531 has 4 divisors (see below), whose sum is σ = 699864. Its totient is φ = 583200.

The previous prime is 641521. The next prime is 641549. The reversal of 641531 is 135146.

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 641531 - 2⁶ = 641467 is a prime.

It is a super-2 number, since 2×641531² = 823124047922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (641521) 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 3 ways as a sum of consecutive naturals, for example, 29150 + ... + 29171.

It is an arithmetic number, because the mean of its divisors is an integer number (174966).

2⁶⁴¹⁵³¹ is an apocalyptic number.

641531 is a deficient number, since it is larger than the sum of its proper divisors (58333).

641531 is a wasteful number, since it uses less digits than its factorization.

641531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58332.

The product of its digits is 360, while the sum is 20.

The square root of 641531 is about 800.9563034273. The cubic root of 641531 is about 86.2460503687.

Adding to 641531 its reverse (135146), we get a palindrome (776677).

It can be divided in two parts, 6415 and 31, that added together give a palindrome (6446).

The spelling of 641531 in words is "six hundred forty-one thousand, five hundred thirty-one".