81998160 has 40 divisors (see below), whose sum is σ = 254195040. Its totient is φ = 21866112.

The previous prime is 81998143. The next prime is 81998177. The reversal of 81998160 is 6189918.

It is an interprime number because it is at equal distance from previous prime (81998143) and next prime (81998177).

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, 170590 + ... + 171069.

It is an arithmetic number, because the mean of its divisors is an integer number (6354876).

Almost surely, 2^81998160 is an apocalyptic number.

81998160 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81998160 is an abundant number, since it is smaller than the sum of its proper divisors (172196880).

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

81998160 is a wasteful number, since it uses less digits than its factorization.

81998160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 341675 (or 341669 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 42.

The square root of 81998160 is about 9055.2835405635. The cubic root of 81998160 is about 434.4448990217. Note that the first 3 decimals are identical.

The spelling of 81998160 in words is "eighty-one million, nine hundred ninety-eight thousand, one hundred sixty".