1666665737 has 24 divisors (see below), whose sum is σ = 1959948648. Its totient is φ = 1411153920.

The previous prime is 1666665713. The next prime is 1666665743. The reversal of 1666665737 is 7375666661.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 525509776 + 1141155961 = 22924^2 + 33781^2 .

It is not a de Polignac number, because 1666665737 - 2⁶ = 1666665673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666665797) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 195353 + ... + 203705.

It is an arithmetic number, because the mean of its divisors is an integer number (81664527).

Almost surely, 2^1666665737 is an apocalyptic number.

1666665737 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1666665737 is a deficient number, since it is larger than the sum of its proper divisors (293282911).

1666665737 is a wasteful number, since it uses less digits than its factorization.

1666665737 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8489 (or 8478 counting only the distinct ones).

The product of its digits is 5715360, while the sum is 53.

The square root of 1666665737 is about 40824.8176603399. The cubic root of 1666665737 is about 1185.6308810483.

The spelling of 1666665737 in words is "one billion, six hundred sixty-six million, six hundred sixty-five thousand, seven hundred thirty-seven".