641605986 has 24 divisors (see below), whose sum is σ = 1588738944. Its totient is φ = 183315960.

The previous prime is 641605981. The next prime is 641606033. The reversal of 641605986 is 689506146.

It is not an unprimeable number, because it can be changed into a prime (641605981) 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 11 ways as a sum of consecutive naturals, for example, 2545930 + ... + 2546181.

It is an arithmetic number, because the mean of its divisors is an integer number (66197456).

Almost surely, 2^641605986 is an apocalyptic number.

641605986 is an abundant number, since it is smaller than the sum of its proper divisors (947132958).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

641605986 is a wasteful number, since it uses less digits than its factorization.

641605986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5092126 (or 5092123 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 641605986 is about 25329.9424792083. The cubic root of 641605986 is about 862.4941055678.

The spelling of 641605986 in words is "six hundred forty-one million, six hundred five thousand, nine hundred eighty-six".