231601666 has 4 divisors (see below), whose sum is σ = 347402502. Its totient is φ = 115800832.

The previous prime is 231601663. The next prime is 231601673. The reversal of 231601666 is 666106132.

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., 221861025 + 9740641 = 14895^2 + 3121^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (231601663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 57900415 + ... + 57900418.

Almost surely, 2^231601666 is an apocalyptic number.

231601666 is a deficient number, since it is larger than the sum of its proper divisors (115800836).

231601666 is a wasteful number, since it uses less digits than its factorization.

231601666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115800835.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 231601666 is about 15218.4646400351. The cubic root of 231601666 is about 614.1114946406. Note that the first 3 decimals are identical.

Adding to 231601666 its reverse (666106132), we get a palindrome (897707798).

The spelling of 231601666 in words is "two hundred thirty-one million, six hundred one thousand, six hundred sixty-six".