87640439 has 2 divisors, whose sum is σ = 87640440. Its totient is φ = 87640438.

The previous prime is 87640433. The next prime is 87640451. The reversal of 87640439 is 93404678.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 87640439 - 2⁸ = 87640183 is a prime.

It is a super-2 number, since 2×87640439² = 15361693096225442, which contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 87640396 and 87640405.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87640433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43820219 + 43820220.

It is an arithmetic number, because the mean of its divisors is an integer number (43820220).

Almost surely, 2^87640439 is an apocalyptic number.

87640439 is a deficient number, since it is larger than the sum of its proper divisors (1).

87640439 is an equidigital number, since it uses as much as digits as its factorization.

87640439 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 145152, while the sum is 41.

The square root of 87640439 is about 9361.6472375325. The cubic root of 87640439 is about 444.1893907689.

The spelling of 87640439 in words is "eighty-seven million, six hundred forty thousand, four hundred thirty-nine".