641660587 has 2 divisors, whose sum is σ = 641660588. Its totient is φ = 641660586.

The previous prime is 641660573. The next prime is 641660627. The reversal of 641660587 is 785066146.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-641660587 is a prime.

It is not a weakly prime, because it can be changed into another prime (641660507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320830293 + 320830294.

It is an arithmetic number, because the mean of its divisors is an integer number (320830294).

Almost surely, 2^641660587 is an apocalyptic number.

641660587 is a deficient number, since it is larger than the sum of its proper divisors (1).

641660587 is an equidigital number, since it uses as much as digits as its factorization.

641660587 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 43.

The square root of 641660587 is about 25331.0202518572. The cubic root of 641660587 is about 862.5185711047.

The spelling of 641660587 in words is "six hundred forty-one million, six hundred sixty thousand, five hundred eighty-seven".