31989761 has 2 divisors, whose sum is σ = 31989762. Its totient is φ = 31989760.

The previous prime is 31989731. The next prime is 31989773. The reversal of 31989761 is 16798913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30250000 + 1739761 = 5500^2 + 1319^2 .

It is a cyclic number.

It is not a de Polignac number, because 31989761 - 2¹⁴ = 31973377 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (31989701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15994880 + 15994881.

It is an arithmetic number, because the mean of its divisors is an integer number (15994881).

It is a Proth number, since it is equal to 3905 ⋅ 2¹³ + 1 and 3905 < 2¹³.

Almost surely, 2^31989761 is an apocalyptic number.

It is an amenable number.

31989761 is a deficient number, since it is larger than the sum of its proper divisors (1).

31989761 is an equidigital number, since it uses as much as digits as its factorization.

31989761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 44.

The square root of 31989761 is about 5655.9491687956. The cubic root of 31989761 is about 317.4463455328.

The spelling of 31989761 in words is "thirty-one million, nine hundred eighty-nine thousand, seven hundred sixty-one".