81687006 has 72 divisors (see below), whose sum is σ = 193100544. Its totient is φ = 24936960.

The previous prime is 81686993. The next prime is 81687017. The reversal of 81687006 is 60078618.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 213091 + ... + 213473.

It is an arithmetic number, because the mean of its divisors is an integer number (2681952).

Almost surely, 2^81687006 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81687006, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96550272).

81687006 is an abundant number, since it is smaller than the sum of its proper divisors (111413538).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81687006 is a wasteful number, since it uses less digits than its factorization.

81687006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466 (or 446 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 81687006 is about 9038.0864125101. The cubic root of 81687006 is about 433.8946809220.

The spelling of 81687006 in words is "eighty-one million, six hundred eighty-seven thousand, six".