21516230 has 8 divisors (see below), whose sum is σ = 38729232. Its totient is φ = 8606488.

The previous prime is 21516197. The next prime is 21516233. The reversal of 21516230 is 3261512.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21516233) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1075802 + ... + 1075821.

It is an arithmetic number, because the mean of its divisors is an integer number (4841154).

Almost surely, 2^21516230 is an apocalyptic number.

21516230 is a deficient number, since it is larger than the sum of its proper divisors (17213002).

21516230 is a wasteful number, since it uses less digits than its factorization.

21516230 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2151630.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21516230 is about 4638.5590434962. The cubic root of 21516230 is about 278.1348396132.

Adding to 21516230 its reverse (3261512), we get a palindrome (24777742).

The spelling of 21516230 in words is "twenty-one million, five hundred sixteen thousand, two hundred thirty".