31661664240161 has 4 divisors (see below), whose sum is σ = 32397982013232. Its totient is φ = 30925346467092.

The previous prime is 31661664240139. The next prime is 31661664240187. The reversal of 31661664240161 is 16104246616613.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31661664240161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31661664240191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 368158886471 + ... + 368158886556.

It is an arithmetic number, because the mean of its divisors is an integer number (8099495503308).

Almost surely, 2^{31661664240161} is an apocalyptic number.

It is an amenable number.

31661664240161 is a deficient number, since it is larger than the sum of its proper divisors (736317773071).

31661664240161 is an equidigital number, since it uses as much as digits as its factorization.

31661664240161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 736317773070.

The product of its (nonzero) digits is 746496, while the sum is 47.

The spelling of 31661664240161 in words is "thirty-one trillion, six hundred sixty-one billion, six hundred sixty-four million, two hundred forty thousand, one hundred sixty-one".