31661649 has 12 divisors (see below), whose sum is σ = 47310900. Its totient is φ = 20379744.

The previous prime is 31661611. The next prime is 31661681. The reversal of 31661649 is 94616613.

31661649 is a `hidden beast` number, since 3 + 1 + 6 + 6 + 1 + 649 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 25250625 + 6411024 = 5025^2 + 2532^2 .

It is not a de Polignac number, because 31661649 - 2¹⁵ = 31628881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31661689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60394 + ... + 60915.

It is an arithmetic number, because the mean of its divisors is an integer number (3942575).

Almost surely, 2^31661649 is an apocalyptic number.

It is an amenable number.

31661649 is a deficient number, since it is larger than the sum of its proper divisors (15649251).

31661649 is a wasteful number, since it uses less digits than its factorization.

31661649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121344 (or 121341 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 31661649 is about 5626.8684896663. The cubic root of 31661649 is about 316.3572876208.

The spelling of 31661649 in words is "thirty-one million, six hundred sixty-one thousand, six hundred forty-nine".