6615906661 has 8 divisors (see below), whose sum is σ = 8142654464. Its totient is φ = 5234563440.

The previous prime is 6615906659. The next prime is 6615906667. The reversal of 6615906661 is 1666095166.

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

It is a cyclic number.

It is not a de Polignac number, because 6615906661 - 2¹ = 6615906659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6615906667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36351045 + ... + 36351226.

It is an arithmetic number, because the mean of its divisors is an integer number (1017831808).

Almost surely, 2^6615906661 is an apocalyptic number.

It is an amenable number.

6615906661 is a deficient number, since it is larger than the sum of its proper divisors (1526747803).

6615906661 is a wasteful number, since it uses less digits than its factorization.

6615906661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72702291.

The product of its (nonzero) digits is 349920, while the sum is 46.

The square root of 6615906661 is about 81338.2238618474. The cubic root of 6615906661 is about 1877.2831835386.

It can be divided in two parts, 6615 and 906661, that added together give a triangular number (913276 = T₁₃₅₁).

The spelling of 6615906661 in words is "six billion, six hundred fifteen million, nine hundred six thousand, six hundred sixty-one".