31218949 has 2 divisors, whose sum is σ = 31218950. Its totient is φ = 31218948.

The previous prime is 31218923. The next prime is 31218973. The reversal of 31218949 is 94981213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26884225 + 4334724 = 5185^2 + 2082^2 .

It is a cyclic number.

It is not a de Polignac number, because 31218949 - 2¹¹ = 31216901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31218049) 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 as a sum of consecutive naturals, namely, 15609474 + 15609475.

It is an arithmetic number, because the mean of its divisors is an integer number (15609475).

Almost surely, 2^31218949 is an apocalyptic number.

It is an amenable number.

31218949 is a deficient number, since it is larger than the sum of its proper divisors (1).

31218949 is an equidigital number, since it uses as much as digits as its factorization.

31218949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 37.

The square root of 31218949 is about 5587.3919676357. The cubic root of 31218949 is about 314.8759030784.

The spelling of 31218949 in words is "thirty-one million, two hundred eighteen thousand, nine hundred forty-nine".