31132215661 has 4 divisors (see below), whose sum is σ = 31132944000. Its totient is φ = 31131487324.

The previous prime is 31132215623. The next prime is 31132215677. The reversal of 31132215661 is 16651223113.

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 not a de Polignac number, because 31132215661 - 2¹⁹ = 31131691373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31132215761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 295771 + ... + 386968.

It is an arithmetic number, because the mean of its divisors is an integer number (7783236000).

Almost surely, 2^31132215661 is an apocalyptic number.

It is an amenable number.

31132215661 is a deficient number, since it is larger than the sum of its proper divisors (728339).

31132215661 is an equidigital number, since it uses as much as digits as its factorization.

31132215661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 728338.

The product of its digits is 6480, while the sum is 31.

Adding to 31132215661 its reverse (16651223113), we get a palindrome (47783438774).

The spelling of 31132215661 in words is "thirty-one billion, one hundred thirty-two million, two hundred fifteen thousand, six hundred sixty-one".