21125187 has 12 divisors (see below), whose sum is σ = 31339360. Its totient is φ = 13702608.

The previous prime is 21125183. The next prime is 21125219. The reversal of 21125187 is 78152112.

It is not a de Polignac number, because 21125187 - 2² = 21125183 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21125187.

It is not an unprimeable number, because it can be changed into a prime (21125183) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 31387 + ... + 32052.

Almost surely, 2^21125187 is an apocalyptic number.

21125187 is a deficient number, since it is larger than the sum of its proper divisors (10214173).

21125187 is a wasteful number, since it uses less digits than its factorization.

21125187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63482 (or 63479 counting only the distinct ones).

The product of its digits is 1120, while the sum is 27.

The square root of 21125187 is about 4596.2144205857. The cubic root of 21125187 is about 276.4395563667.

Adding to 21125187 its reverse (78152112), we get a palindrome (99277299).

It can be divided in two parts, 21125 and 187, that added together give a palindrome (21312).

The spelling of 21125187 in words is "twenty-one million, one hundred twenty-five thousand, one hundred eighty-seven".