39987109 has 2 divisors, whose sum is σ = 39987110. Its totient is φ = 39987108.

The previous prime is 39987107. The next prime is 39987113. The reversal of 39987109 is 90178993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 36942084 + 3045025 = 6078^2 + 1745^2 .

It is a cyclic number.

It is not a de Polignac number, because 39987109 - 2¹ = 39987107 is a prime.

Together with 39987107, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39987107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19993554 + 19993555.

It is an arithmetic number, because the mean of its divisors is an integer number (19993555).

Almost surely, 2^39987109 is an apocalyptic number.

It is an amenable number.

39987109 is a deficient number, since it is larger than the sum of its proper divisors (1).

39987109 is an equidigital number, since it uses as much as digits as its factorization.

39987109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 122472, while the sum is 46.

The square root of 39987109 is about 6323.5361151811. The cubic root of 39987109 is about 341.9584465547.

The spelling of 39987109 in words is "thirty-nine million, nine hundred eighty-seven thousand, one hundred nine".