21187000 has 32 divisors (see below), whose sum is σ = 49579920. Its totient is φ = 8474400.

The previous prime is 21186983. The next prime is 21187013. The reversal of 21187000 is 78112.

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, 9594 + ... + 11593.

Almost surely, 2^21187000 is an apocalyptic number.

21187000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21187000 is an abundant number, since it is smaller than the sum of its proper divisors (28392920).

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

21187000 is a wasteful number, since it uses less digits than its factorization.

21187000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21208 (or 21194 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 21187000 is about 4602.9338470154. The cubic root of 21187000 is about 276.7089175970.

The spelling of 21187000 in words is "twenty-one million, one hundred eighty-seven thousand".