641662509 has 16 divisors (see below), whose sum is σ = 901400000. Its totient is φ = 404891136.

The previous prime is 641662507. The next prime is 641662517. The reversal of 641662509 is 905266146.

It is not a de Polignac number, because 641662509 - 2¹ = 641662507 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641662507) 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 in 15 ways as a sum of consecutive naturals, for example, 66687 + ... + 75699.

It is an arithmetic number, because the mean of its divisors is an integer number (56337500).

Almost surely, 2^641662509 is an apocalyptic number.

It is an amenable number.

641662509 is a deficient number, since it is larger than the sum of its proper divisors (259737491).

641662509 is a wasteful number, since it uses less digits than its factorization.

641662509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10284.

The product of its (nonzero) digits is 77760, while the sum is 39.

The square root of 641662509 is about 25331.0581895033. The cubic root of 641662509 is about 862.5194322864.

The spelling of 641662509 in words is "six hundred forty-one million, six hundred sixty-two thousand, five hundred nine".