1664330334661 has 4 divisors (see below), whose sum is σ = 1664335139692. Its totient is φ = 1664325529632.

The previous prime is 1664330334631. The next prime is 1664330334673.

1664330334661 is nontrivially palindromic in base 10.

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

It can be written as a sum of positive squares in 2 ways, for example, as 147260225025 + 1517070109636 = 383745^2 + 1231694^2 .

It is a cyclic number.

It is not a de Polignac number, because 1664330334661 - 2⁵ = 1664330334629 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 (1664330334631) 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, 1838880 + ... + 2590393.

It is an arithmetic number, because the mean of its divisors is an integer number (416083784923).

Almost surely, 2^{1664330334661} is an apocalyptic number.

It is an amenable number.

1664330334661 is a deficient number, since it is larger than the sum of its proper divisors (4805031).

1664330334661 is an equidigital number, since it uses as much as digits as its factorization.

1664330334661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4805030.

The product of its (nonzero) digits is 1679616, while the sum is 46.

It can be divided in two parts, 1664330 and 334661, that added together give a palindrome (1998991).

The spelling of 1664330334661 in words is "one trillion, six hundred sixty-four billion, three hundred thirty million, three hundred thirty-four thousand, six hundred sixty-one".