6661601655 has 16 divisors (see below), whose sum is σ = 10663715040. Its totient is φ = 3551136768.

The previous prime is 6661601633. The next prime is 6661601659. The reversal of 6661601655 is 5561061666.

It is not a de Polignac number, because 6661601655 - 2⁶ = 6661601591 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6661601659) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74962 + ... + 137631.

It is an arithmetic number, because the mean of its divisors is an integer number (666482190).

Almost surely, 2^6661601655 is an apocalyptic number.

6661601655 is a deficient number, since it is larger than the sum of its proper divisors (4002113385).

6661601655 is a wasteful number, since it uses less digits than its factorization.

6661601655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214690.

The product of its (nonzero) digits is 194400, while the sum is 42.

The square root of 6661601655 is about 81618.6354639674. The cubic root of 6661601655 is about 1881.5953011563.

The spelling of 6661601655 in words is "six billion, six hundred sixty-one million, six hundred one thousand, six hundred fifty-five".