131858666 has 4 divisors (see below), whose sum is σ = 197788002. Its totient is φ = 65929332.

The previous prime is 131858653. The next prime is 131858669. The reversal of 131858666 is 666858131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666858131 = 887 ⋅751813.

It can be written as a sum of positive squares in only one way, i.e., 129390625 + 2468041 = 11375^2 + 1571^2 .

It is not an unprimeable number, because it can be changed into a prime (131858669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32964665 + ... + 32964668.

Almost surely, 2^131858666 is an apocalyptic number.

131858666 is a deficient number, since it is larger than the sum of its proper divisors (65929336).

131858666 is an equidigital number, since it uses as much as digits as its factorization.

131858666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65929335.

The product of its digits is 207360, while the sum is 44.

The square root of 131858666 is about 11482.9728729106. The cubic root of 131858666 is about 508.9825492606.

The spelling of 131858666 in words is "one hundred thirty-one million, eight hundred fifty-eight thousand, six hundred sixty-six".