131664681 has 6 divisors (see below), whose sum is σ = 190182330. Its totient is φ = 87776448.

The previous prime is 131664679. The next prime is 131664707. The reversal of 131664681 is 186466131.

131664681 is a `hidden beast` number, since 1 + 3 + 1 + 6 + 646 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 93026025 + 38638656 = 9645^2 + 6216^2 .

It is not a de Polignac number, because 131664681 - 2¹ = 131664679 is a prime.

It is a super-4 number, since 4×131664681⁴ (a number of 34 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (131664641) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7314696 + ... + 7314713.

It is an arithmetic number, because the mean of its divisors is an integer number (31697055).

Almost surely, 2^131664681 is an apocalyptic number.

It is an amenable number.

131664681 is a deficient number, since it is larger than the sum of its proper divisors (58517649).

131664681 is a wasteful number, since it uses less digits than its factorization.

131664681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14629415 (or 14629412 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 131664681 is about 11474.5231273461. The cubic root of 131664681 is about 508.7328287564.

The spelling of 131664681 in words is "one hundred thirty-one million, six hundred sixty-four thousand, six hundred eighty-one".