31491749 has 2 divisors, whose sum is σ = 31491750. Its totient is φ = 31491748.

The previous prime is 31491737. The next prime is 31491787. The reversal of 31491749 is 94719413.

It is an a-pointer prime, because the next prime (31491787) can be obtained adding 31491749 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27227524 + 4264225 = 5218^2 + 2065^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31491749 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31491149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15745874 + 15745875.

It is an arithmetic number, because the mean of its divisors is an integer number (15745875).

Almost surely, 2^31491749 is an apocalyptic number.

It is an amenable number.

31491749 is a deficient number, since it is larger than the sum of its proper divisors (1).

31491749 is an equidigital number, since it uses as much as digits as its factorization.

31491749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 38.

The square root of 31491749 is about 5611.7509745177. The cubic root of 31491749 is about 315.7904027219.

The spelling of 31491749 in words is "thirty-one million, four hundred ninety-one thousand, seven hundred forty-nine".