81664080 has 40 divisors (see below), whose sum is σ = 253159392. Its totient is φ = 21777024.

The previous prime is 81664067. The next prime is 81664111. The reversal of 81664080 is 8046618.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 169894 + ... + 170373.

Almost surely, 2^81664080 is an apocalyptic number.

81664080 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81664080 is an abundant number, since it is smaller than the sum of its proper divisors (171495312).

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

81664080 is a wasteful number, since it uses less digits than its factorization.

81664080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340283 (or 340277 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 81664080 is about 9036.8180240613. The cubic root of 81664080 is about 433.8540853173.

It can be divided in two parts, 8166 and 4080, that added together give a triangular number (12246 = T₁₅₆).

The spelling of 81664080 in words is "eighty-one million, six hundred sixty-four thousand, eighty".