1666392381 has 12 divisors (see below), whose sum is σ = 2412901660. Its totient is φ = 1108209600.

The previous prime is 1666392353. The next prime is 1666392433. The reversal of 1666392381 is 1832936661.

It can be written as a sum of positive squares in 2 ways, for example, as 1408500900 + 257891481 = 37530^2 + 16059^2 .

It is not a de Polignac number, because 1666392381 - 2¹¹ = 1666390333 is a prime.

It is a super-2 number, since 2×1666392381² = 5553727134909698322, 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 (1666390381) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 222670 + ... + 230031.

Almost surely, 2^1666392381 is an apocalyptic number.

It is an amenable number.

1666392381 is a deficient number, since it is larger than the sum of its proper divisors (746509279).

1666392381 is a wasteful number, since it uses less digits than its factorization.

1666392381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453116 (or 453113 counting only the distinct ones).

The product of its digits is 279936, while the sum is 45.

The square root of 1666392381 is about 40821.4696085283. The cubic root of 1666392381 is about 1185.5660576050.

The spelling of 1666392381 in words is "one billion, six hundred sixty-six million, three hundred ninety-two thousand, three hundred eighty-one".