81708587 has 2 divisors, whose sum is σ = 81708588. Its totient is φ = 81708586.

The previous prime is 81708553. The next prime is 81708589. The reversal of 81708587 is 78580718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81708587 - 2²⁴ = 64931371 is a prime.

Together with 81708589, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81708589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40854293 + 40854294.

It is an arithmetic number, because the mean of its divisors is an integer number (40854294).

Almost surely, 2^81708587 is an apocalyptic number.

81708587 is a deficient number, since it is larger than the sum of its proper divisors (1).

81708587 is an equidigital number, since it uses as much as digits as its factorization.

81708587 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 125440, while the sum is 44.

The square root of 81708587 is about 9039.2802257702. The cubic root of 81708587 is about 433.9328879640.

The spelling of 81708587 in words is "eighty-one million, seven hundred eight thousand, five hundred eighty-seven".