31661145 has 16 divisors (see below), whose sum is σ = 56286720. Its totient is φ = 16885872.

The previous prime is 31661141. The next prime is 31661167. The reversal of 31661145 is 54116613.

31661145 is a `hidden beast` number, since 3 + 1 + 6 + 611 + 45 = 666.

It is not a de Polignac number, because 31661145 - 2² = 31661141 is a prime.

It is a super-2 number, since 2×31661145² = 2004856205422050, which contains 22 as substring.

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 (31661141) 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 15 ways as a sum of consecutive naturals, for example, 117129 + ... + 117398.

It is an arithmetic number, because the mean of its divisors is an integer number (3517920).

Almost surely, 2^31661145 is an apocalyptic number.

It is an amenable number.

31661145 is a deficient number, since it is larger than the sum of its proper divisors (24625575).

31661145 is a wasteful number, since it uses less digits than its factorization.

31661145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234541 (or 234535 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 31661145 is about 5626.8237043647. The cubic root of 31661145 is about 316.3556089872.

Adding to 31661145 its reverse (54116613), we get a palindrome (85777758).

The spelling of 31661145 in words is "thirty-one million, six hundred sixty-one thousand, one hundred forty-five".