1666751837 has 4 divisors (see below), whose sum is σ = 1667789340. Its totient is φ = 1665714336.

The previous prime is 1666751819. The next prime is 1666751843. The reversal of 1666751837 is 7381576661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7381576661 = 2399 ⋅3076939.

It can be written as a sum of positive squares in 2 ways, for example, as 888397636 + 778354201 = 29806^2 + 27899^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666751837 - 2¹² = 1666747741 is a prime.

It is a super-2 number, since 2×1666751837² = 5556123372285749138, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666751237) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 516338 + ... + 519555.

It is an arithmetic number, because the mean of its divisors is an integer number (416947335).

Almost surely, 2^1666751837 is an apocalyptic number.

It is an amenable number.

1666751837 is a deficient number, since it is larger than the sum of its proper divisors (1037503).

1666751837 is a wasteful number, since it uses less digits than its factorization.

1666751837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1037502.

The product of its digits is 1270080, while the sum is 50.

The square root of 1666751837 is about 40825.8721523497. The cubic root of 1666751837 is about 1185.6512972719.

The spelling of 1666751837 in words is "one billion, six hundred sixty-six million, seven hundred fifty-one thousand, eight hundred thirty-seven".