131121666 has 80 divisors (see below), whose sum is σ = 330289344. Its totient is φ = 38576736.

The previous prime is 131121637. The next prime is 131121701. The reversal of 131121666 is 666121131.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 47085 + ... + 49791.

Almost surely, 2^131121666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 131121666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165144672).

131121666 is an abundant number, since it is smaller than the sum of its proper divisors (199167678).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

131121666 is a wasteful number, since it uses less digits than its factorization.

131121666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2757 (or 2748 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 131121666 is about 11450.8369126453. The cubic root of 131121666 is about 508.0324885705.

Adding to 131121666 its reverse (666121131), we get a palindrome (797242797).

The spelling of 131121666 in words is "one hundred thirty-one million, one hundred twenty-one thousand, six hundred sixty-six".