21031230 has 64 divisors (see below), whose sum is σ = 55696896. Its totient is φ = 5040000.

The previous prime is 21031229. The next prime is 21031253. The reversal of 21031230 is 3213012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 33015 + ... + 33645.

It is an arithmetic number, because the mean of its divisors is an integer number (870264).

Almost surely, 2^21031230 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21031230, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27848448).

21031230 is an abundant number, since it is smaller than the sum of its proper divisors (34665666).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21031230 is a wasteful number, since it uses less digits than its factorization.

21031230 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 753.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21031230 is about 4585.9819014034. The cubic root of 21031230 is about 276.0291137110.

Adding to 21031230 its reverse (3213012), we get a palindrome (24244242).

It can be divided in two parts, 2103 and 1230, that added together give a palindrome (3333).

The spelling of 21031230 in words is "twenty-one million, thirty-one thousand, two hundred thirty".