31389309 has 16 divisors (see below), whose sum is σ = 53146240. Its totient is φ = 17936640.

The previous prime is 31389301. The next prime is 31389317. The reversal of 31389309 is 90398313.

It is an interprime number because it is at equal distance from previous prime (31389301) and next prime (31389317).

It is not a de Polignac number, because 31389309 - 2³ = 31389301 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31389301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 82852 + ... + 83229.

It is an arithmetic number, because the mean of its divisors is an integer number (3321640).

Almost surely, 2^31389309 is an apocalyptic number.

It is an amenable number.

31389309 is a deficient number, since it is larger than the sum of its proper divisors (21756931).

31389309 is a wasteful number, since it uses less digits than its factorization.

31389309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166097 (or 166091 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 31389309 is about 5602.6162638539. The cubic root of 31389309 is about 315.4476175987.

The spelling of 31389309 in words is "thirty-one million, three hundred eighty-nine thousand, three hundred nine".