6661628261666 has 16 divisors (see below), whose sum is σ = 11419971062400. Its totient is φ = 2854974315840.

The previous prime is 6661628261653. The next prime is 6661628261707.

It is a happy number.

6661628261666 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 6661628261599 and 6661628261608.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5458010 + ... + 6566058.

It is an arithmetic number, because the mean of its divisors is an integer number (713748191400).

Almost surely, 2^{6661628261666} is an apocalyptic number.

6661628261666 is a deficient number, since it is larger than the sum of its proper divisors (4758342800734).

6661628261666 is a wasteful number, since it uses less digits than its factorization.

6661628261666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537489.

The product of its digits is 53747712, while the sum is 62.

The spelling of 6661628261666 in words is "six trillion, six hundred sixty-one billion, six hundred twenty-eight million, two hundred sixty-one thousand, six hundred sixty-six".