21187055 has 8 divisors (see below), whose sum is σ = 25596000. Its totient is φ = 16835296.

The previous prime is 21187027. The next prime is 21187063. The reversal of 21187055 is 55078112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21187055 - 2⁸ = 21186799 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13475 + ... + 14964.

It is an arithmetic number, because the mean of its divisors is an integer number (3199500).

Almost surely, 2^21187055 is an apocalyptic number.

21187055 is a deficient number, since it is larger than the sum of its proper divisors (4408945).

21187055 is a wasteful number, since it uses less digits than its factorization.

21187055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28593.

The product of its (nonzero) digits is 2800, while the sum is 29.

The square root of 21187055 is about 4602.9398214619. The cubic root of 21187055 is about 276.7091570359.

The spelling of 21187055 in words is "twenty-one million, one hundred eighty-seven thousand, fifty-five".