81887705 has 8 divisors (see below), whose sum is σ = 102537792. Its totient is φ = 62661808.

The previous prime is 81887699. The next prime is 81887723. The reversal of 81887705 is 50778818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81887705 - 2¹² = 81883609 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 355919 + ... + 356148.

It is an arithmetic number, because the mean of its divisors is an integer number (12817224).

Almost surely, 2^81887705 is an apocalyptic number.

It is an amenable number.

81887705 is a deficient number, since it is larger than the sum of its proper divisors (20650087).

81887705 is a wasteful number, since it uses less digits than its factorization.

81887705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 712095.

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

The square root of 81887705 is about 9049.1825597675. The cubic root of 81887705 is about 434.2497394631.

The spelling of 81887705 in words is "eighty-one million, eight hundred eighty-seven thousand, seven hundred five".