1230213521 has 4 divisors (see below), whose sum is σ = 1247540544. Its totient is φ = 1212886500.

The previous prime is 1230213497. The next prime is 1230213529. The reversal of 1230213521 is 1253120321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1230213521 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1230213493 and 1230213502.

It is not an unprimeable number, because it can be changed into a prime (1230213529) by changing a digit.

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, 8663405 + ... + 8663546.

It is an arithmetic number, because the mean of its divisors is an integer number (311885136).

Almost surely, 2^1230213521 is an apocalyptic number.

It is an amenable number.

1230213521 is a deficient number, since it is larger than the sum of its proper divisors (17327023).

1230213521 is an equidigital number, since it uses as much as digits as its factorization.

1230213521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17327022.

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

The square root of 1230213521 is about 35074.3997952923. The cubic root of 1230213521 is about 1071.5032648058.

Adding to 1230213521 its reverse (1253120321), we get a palindrome (2483333842).

The spelling of 1230213521 in words is "one billion, two hundred thirty million, two hundred thirteen thousand, five hundred twenty-one".