31661221061 has 16 divisors (see below), whose sum is σ = 32835611520. Its totient is φ = 30514659840.

The previous prime is 31661221027. The next prime is 31661221063. The reversal of 31661221061 is 16012216613.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 31661221061 - 2¹⁴ = 31661204677 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 (31661221063) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 558650 + ... + 612708.

It is an arithmetic number, because the mean of its divisors is an integer number (2052225720).

Almost surely, 2^31661221061 is an apocalyptic number.

It is an amenable number.

31661221061 is a deficient number, since it is larger than the sum of its proper divisors (1174390459).

31661221061 is a wasteful number, since it uses less digits than its factorization.

31661221061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54316.

The product of its (nonzero) digits is 2592, while the sum is 29.

Adding to 31661221061 its reverse (16012216613), we get a palindrome (47673437674).

The spelling of 31661221061 in words is "thirty-one billion, six hundred sixty-one million, two hundred twenty-one thousand, sixty-one".