39931987 has 2 divisors, whose sum is σ = 39931988. Its totient is φ = 39931986.

The previous prime is 39931973. The next prime is 39932023. The reversal of 39931987 is 78913993.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 39931987 - 2¹⁵ = 39899219 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 39931987.

It is not a weakly prime, because it can be changed into another prime (39931187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19965993 + 19965994.

It is an arithmetic number, because the mean of its divisors is an integer number (19965994).

Almost surely, 2^39931987 is an apocalyptic number.

39931987 is a deficient number, since it is larger than the sum of its proper divisors (1).

39931987 is an equidigital number, since it uses as much as digits as its factorization.

39931987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 367416, while the sum is 49.

The square root of 39931987 is about 6319.1761330097. The cubic root of 39931987 is about 341.8012450476.

The spelling of 39931987 in words is "thirty-nine million, nine hundred thirty-one thousand, nine hundred eighty-seven".