21368530 has 8 divisors (see below), whose sum is σ = 38463372. Its totient is φ = 8547408.

The previous prime is 21368527. The next prime is 21368531. The reversal of 21368530 is 3586312.

It can be written as a sum of positive squares in 2 ways, for example, as 18515809 + 2852721 = 4303^2 + 1689^2 .

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

It is a super-2 number, since 2×21368530² = 913228148721800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21368531) 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 3 ways as a sum of consecutive naturals, for example, 1068417 + ... + 1068436.

Almost surely, 2^21368530 is an apocalyptic number.

21368530 is a deficient number, since it is larger than the sum of its proper divisors (17094842).

21368530 is a wasteful number, since it uses less digits than its factorization.

21368530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2136860.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 21368530 is about 4622.6107342064. The cubic root of 21368530 is about 277.4969509716.

The spelling of 21368530 in words is "twenty-one million, three hundred sixty-eight thousand, five hundred thirty".