31218072 has 32 divisors (see below), whose sum is σ = 78246000. Its totient is φ = 10379264.

The previous prime is 31218067. The next prime is 31218073. The reversal of 31218072 is 27081213.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31218073) 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 7 ways as a sum of consecutive naturals, for example, 9328 + ... + 12224.

Almost surely, 2^31218072 is an apocalyptic number.

It is an amenable number.

31218072 is an abundant number, since it is smaller than the sum of its proper divisors (47027928).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31218072 is a wasteful number, since it uses less digits than its factorization.

31218072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3355 (or 3351 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 31218072 is about 5587.3134868199. The cubic root of 31218072 is about 314.8729545620.

Adding to 31218072 its reverse (27081213), we get a palindrome (58299285).

The spelling of 31218072 in words is "thirty-one million, two hundred eighteen thousand, seventy-two".