31218742 has 8 divisors (see below), whose sum is σ = 47469816. Its totient is φ = 15395472.

The previous prime is 31218739. The next prime is 31218743. The reversal of 31218742 is 24781213.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 31218742.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31218743) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106768 + ... + 107059.

It is an arithmetic number, because the mean of its divisors is an integer number (5933727).

Almost surely, 2^31218742 is an apocalyptic number.

31218742 is a deficient number, since it is larger than the sum of its proper divisors (16251074).

31218742 is a wasteful number, since it uses less digits than its factorization.

31218742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213902.

The product of its digits is 2688, while the sum is 28.

The square root of 31218742 is about 5587.3734437569. The cubic root of 31218742 is about 314.8752071394.

Adding to 31218742 its reverse (24781213), we get a palindrome (55999955).

The spelling of 31218742 in words is "thirty-one million, two hundred eighteen thousand, seven hundred forty-two".