21513230 has 16 divisors (see below), whose sum is σ = 39455424. Its totient is φ = 8442720.

The previous prime is 21513227. The next prime is 21513241. The reversal of 21513230 is 3231512.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21513199 and 21513208.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19766 + ... + 20825.

It is an arithmetic number, because the mean of its divisors is an integer number (2465964).

Almost surely, 2^21513230 is an apocalyptic number.

21513230 is a deficient number, since it is larger than the sum of its proper divisors (17942194).

21513230 is a wasteful number, since it uses less digits than its factorization.

21513230 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40651.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21513230 is about 4638.2356559364. The cubic root of 21513230 is about 278.1219122664.

Adding to 21513230 its reverse (3231512), we get a palindrome (24744742).

The spelling of 21513230 in words is "twenty-one million, five hundred thirteen thousand, two hundred thirty".