1666880101 has 2 divisors, whose sum is σ = 1666880102. Its totient is φ = 1666880100.

The previous prime is 1666880053. The next prime is 1666880113. The reversal of 1666880101 is 1010886661.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1023040225 + 643839876 = 31985^2 + 25374^2 .

It is an emirp because it is prime and its reverse (1010886661) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1010889991 and 1999880101.

It is a cyclic number.

It is not a de Polignac number, because 1666880101 - 2⁹ = 1666879589 is a prime.

It is a super-2 number, since 2×1666880101² = 5556978542219540402, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666880191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833440050 + 833440051.

It is an arithmetic number, because the mean of its divisors is an integer number (833440051).

Almost surely, 2^1666880101 is an apocalyptic number.

It is an amenable number.

1666880101 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666880101 is an equidigital number, since it uses as much as digits as its factorization.

1666880101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 1666880101 is about 40827.4429887545. The cubic root of 1666880101 is about 1185.6817102132.

It can be divided in two parts, 16668 and 80101, that added together give a palindrome (96769).

The spelling of 1666880101 in words is "one billion, six hundred sixty-six million, eight hundred eighty thousand, one hundred one".