21187488 has 96 divisors (see below), whose sum is σ = 65197440. Its totient is φ = 5898240.

The previous prime is 21187469. The next prime is 21187511. The reversal of 21187488 is 88478112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27168 + ... + 27936.

It is an arithmetic number, because the mean of its divisors is an integer number (679140).

Almost surely, 2^21187488 is an apocalyptic number.

21187488 is a gapful number since it is divisible by the number (28) 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 21187488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32598720).

21187488 is an abundant number, since it is smaller than the sum of its proper divisors (44009952).

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

21187488 is a wasteful number, since it uses less digits than its factorization.

21187488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 830 (or 822 counting only the distinct ones).

The product of its digits is 28672, while the sum is 39.

The square root of 21187488 is about 4602.9868563792. The cubic root of 21187488 is about 276.7110420587.

The spelling of 21187488 in words is "twenty-one million, one hundred eighty-seven thousand, four hundred eighty-eight".