31661361 has 20 divisors (see below), whose sum is σ = 50080932. Its totient is φ = 19865088.

The previous prime is 31661351. The next prime is 31661369. The reversal of 31661361 is 16316613.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 25310961 + 6350400 = 5031^2 + 2520^2 .

It is not a de Polignac number, because 31661361 - 2¹³ = 31653169 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31661369) 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 19 ways as a sum of consecutive naturals, for example, 10120 + ... + 12873.

Almost surely, 2^31661361 is an apocalyptic number.

It is an amenable number.

31661361 is a deficient number, since it is larger than the sum of its proper divisors (18419571).

31661361 is a wasteful number, since it uses less digits than its factorization.

31661361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23022 (or 23013 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 31661361 is about 5626.8428981090. The cubic root of 31661361 is about 316.3563284038.

Adding to 31661361 its reverse (16316613), we get a palindrome (47977974).

The spelling of 31661361 in words is "thirty-one million, six hundred sixty-one thousand, three hundred sixty-one".