31909109 has 2 divisors, whose sum is σ = 31909110. Its totient is φ = 31909108.

The previous prime is 31909093. The next prime is 31909121. The reversal of 31909109 is 90190913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30747025 + 1162084 = 5545^2 + 1078^2 .

It is a cyclic number.

It is not a de Polignac number, because 31909109 - 2⁴ = 31909093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31909159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15954554 + 15954555.

It is an arithmetic number, because the mean of its divisors is an integer number (15954555).

Almost surely, 2^31909109 is an apocalyptic number.

It is an amenable number.

31909109 is a deficient number, since it is larger than the sum of its proper divisors (1).

31909109 is an equidigital number, since it uses as much as digits as its factorization.

31909109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2187, while the sum is 32.

The square root of 31909109 is about 5648.8148314492. The cubic root of 31909109 is about 317.1793410457.

The spelling of 31909109 in words is "thirty-one million, nine hundred nine thousand, one hundred nine".