21155230 has 8 divisors (see below), whose sum is σ = 38079432. Its totient is φ = 8462088.

The previous prime is 21155219. The next prime is 21155257. The reversal of 21155230 is 3255112.

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

It is a junction number, because it is equal to n+sod(n) for n = 21155198 and 21155207.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1057752 + ... + 1057771.

It is an arithmetic number, because the mean of its divisors is an integer number (4759929).

Almost surely, 2^21155230 is an apocalyptic number.

21155230 is a deficient number, since it is larger than the sum of its proper divisors (16924202).

21155230 is a wasteful number, since it uses less digits than its factorization.

21155230 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2115530.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 21155230 is about 4599.4814925163. The cubic root of 21155230 is about 276.5705396601.

The spelling of 21155230 in words is "twenty-one million, one hundred fifty-five thousand, two hundred thirty".