21551230 has 16 divisors (see below), whose sum is σ = 40479264. Its totient is φ = 8245600.

The previous prime is 21551221. The next prime is 21551251. The reversal of 21551230 is 3215512.

It is a junction number, because it is equal to n+sod(n) for n = 21551198 and 21551207.

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 7 ways as a sum of consecutive naturals, for example, 46621 + ... + 47080.

It is an arithmetic number, because the mean of its divisors is an integer number (2529954).

Almost surely, 2^21551230 is an apocalyptic number.

21551230 is a deficient number, since it is larger than the sum of its proper divisors (18928034).

21551230 is a wasteful number, since it uses less digits than its factorization.

21551230 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93731.

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

The square root of 21551230 is about 4642.3302338373. The cubic root of 21551230 is about 278.2855699491.

Adding to 21551230 its reverse (3215512), we get a palindrome (24766742).

The spelling of 21551230 in words is "twenty-one million, five hundred fifty-one thousand, two hundred thirty".