131621661 has 12 divisors (see below), whose sum is σ = 190270080. Its totient is φ = 87678600.

The previous prime is 131621653. The next prime is 131621671. The reversal of 131621661 is 166126131.

131621661 is a `hidden beast` number, since 1 + 31 + 621 + 6 + 6 + 1 = 666.

It is not a de Polignac number, because 131621661 - 2³ = 131621653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131621641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8020 + ... + 18098.

It is an arithmetic number, because the mean of its divisors is an integer number (15855840).

Almost surely, 2^131621661 is an apocalyptic number.

It is an amenable number.

131621661 is a deficient number, since it is larger than the sum of its proper divisors (58648419).

131621661 is a wasteful number, since it uses less digits than its factorization.

131621661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11536 (or 11533 counting only the distinct ones).

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

The square root of 131621661 is about 11472.6483864886. The cubic root of 131621661 is about 508.6774150843.

Adding to 131621661 its reverse (166126131), we get a palindrome (297747792).

The spelling of 131621661 in words is "one hundred thirty-one million, six hundred twenty-one thousand, six hundred sixty-one".