1666751016690 has 24 divisors (see below), whose sum is σ = 4333552643628. Its totient is φ = 444466937760.

The previous prime is 1666751016647. The next prime is 1666751016709. The reversal of 1666751016690 is 966101576661.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1602885134601 + 63865882089 = 1266051^2 + 252717^2 .

It is a super-2 number, since 2×1666751016690² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 9259727781 + ... + 9259727960.

Almost surely, 2^{1666751016690} is an apocalyptic number.

1666751016690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1666751016690 is an abundant number, since it is smaller than the sum of its proper divisors (2666801626938).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1666751016690 is a wasteful number, since it uses less digits than its factorization.

1666751016690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18519455754 (or 18519455751 counting only the distinct ones).

The product of its (nonzero) digits is 2449440, while the sum is 54.

The spelling of 1666751016690 in words is "one trillion, six hundred sixty-six billion, seven hundred fifty-one million, sixteen thousand, six hundred ninety".