641549905 has 8 divisors (see below), whose sum is σ = 771211584. Its totient is φ = 512338800.

The previous prime is 641549903. The next prime is 641549917. The reversal of 641549905 is 509945146.

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

It is not a de Polignac number, because 641549905 - 2¹ = 641549903 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641549903) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109501 + ... + 115210.

It is an arithmetic number, because the mean of its divisors is an integer number (96401448).

Almost surely, 2^641549905 is an apocalyptic number.

It is an amenable number.

641549905 is a deficient number, since it is larger than the sum of its proper divisors (129661679).

641549905 is a wasteful number, since it uses less digits than its factorization.

641549905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225287.

The product of its (nonzero) digits is 194400, while the sum is 43.

The square root of 641549905 is about 25328.8354450022. The cubic root of 641549905 is about 862.4689754296.

The spelling of 641549905 in words is "six hundred forty-one million, five hundred forty-nine thousand, nine hundred five".