21187630 has 16 divisors (see below), whose sum is σ = 38340864. Its totient is φ = 8429920.

The previous prime is 21187619. The next prime is 21187633. The reversal of 21187630 is 3678112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21187633) 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 7 ways as a sum of consecutive naturals, for example, 3637 + ... + 7456.

It is an arithmetic number, because the mean of its divisors is an integer number (2396304).

Almost surely, 2^21187630 is an apocalyptic number.

21187630 is a deficient number, since it is larger than the sum of its proper divisors (17153234).

21187630 is a wasteful number, since it uses less digits than its factorization.

21187630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11291.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 21187630 is about 4603.0022811204. The cubic root of 21187630 is about 276.7116602362.

The spelling of 21187630 in words is "twenty-one million, one hundred eighty-seven thousand, six hundred thirty".