158666666 has 4 divisors (see below), whose sum is σ = 238000002. Its totient is φ = 79333332.

The previous prime is 158666647. The next prime is 158666699. The reversal of 158666666 is 666666851.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 155725441 + 2941225 = 12479^2 + 1715^2 .

It is a super-2 number, since 2×158666666² = 50350221799111112, which contains 22 as substring.

158666666 is a modest number, since divided by 66666 gives 1586 as remainder.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39666665 + ... + 39666668.

Almost surely, 2^158666666 is an apocalyptic number.

158666666 is a deficient number, since it is larger than the sum of its proper divisors (79333336).

158666666 is an equidigital number, since it uses as much as digits as its factorization.

158666666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79333335.

The product of its digits is 1866240, while the sum is 50.

The square root of 158666666 is about 12596.2957253313. The cubic root of 158666666 is about 541.3713043562.

The spelling of 158666666 in words is "one hundred fifty-eight million, six hundred sixty-six thousand, six hundred sixty-six".