19871880 has 128 divisors (see below), whose sum is σ = 69914880. Its totient is φ = 4423680.

The previous prime is 19871773. The next prime is 19871881. The reversal of 19871880 is 8817891.

It is a super-2 number, since 2×19871880² = 789783229468800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (19871881) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 34152 + ... + 34728.

It is an arithmetic number, because the mean of its divisors is an integer number (546210).

Almost surely, 2^19871880 is an apocalyptic number.

19871880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19871880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34957440).

19871880 is an abundant number, since it is smaller than the sum of its proper divisors (50043000).

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

19871880 is a wasteful number, since it uses less digits than its factorization.

19871880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639 (or 635 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 42.

The square root of 19871880 is about 4457.7886894737. The cubic root of 19871880 is about 270.8609009151.

The spelling of 19871880 in words is "nineteen million, eight hundred seventy-one thousand, eight hundred eighty".