18881680 has 20 divisors (see below), whose sum is σ = 43900092. Its totient is φ = 7552640.

The previous prime is 18881677. The next prime is 18881683. The reversal of 18881680 is 8618881.

It is an interprime number because it is at equal distance from previous prime (18881677) and next prime (18881683).

It can be written as a sum of positive squares in 2 ways, for example, as 3640464 + 15241216 = 1908^2 + 3904^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (18881683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 117931 + ... + 118090.

Almost surely, 2^18881680 is an apocalyptic number.

18881680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18881680 is an abundant number, since it is smaller than the sum of its proper divisors (25018412).

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

18881680 is a wasteful number, since it uses less digits than its factorization.

18881680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236034 (or 236028 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 40.

The square root of 18881680 is about 4345.3055128495. The cubic root of 18881680 is about 266.2851070842.

The spelling of 18881680 in words is "eighteen million, eight hundred eighty-one thousand, six hundred eighty".