6606638881691 has 4 divisors (see below), whose sum is σ = 6705245432232. Its totient is φ = 6508032331152.

The previous prime is 6606638881637. The next prime is 6606638881727. The reversal of 6606638881691 is 1961888366066.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6606638881691 - 2¹⁸ = 6606638619547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6606638811691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49303275170 + ... + 49303275303.

It is an arithmetic number, because the mean of its divisors is an integer number (1676311358058).

Almost surely, 2^{6606638881691} is an apocalyptic number.

6606638881691 is a deficient number, since it is larger than the sum of its proper divisors (98606550541).

6606638881691 is an equidigital number, since it uses as much as digits as its factorization.

6606638881691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98606550540.

The product of its (nonzero) digits is 107495424, while the sum is 68.

The spelling of 6606638881691 in words is "six trillion, six hundred six billion, six hundred thirty-eight million, eight hundred eighty-one thousand, six hundred ninety-one".