21254730 has 96 divisors (see below), whose sum is σ = 62544960. Its totient is φ = 4596480.

The previous prime is 21254729. The next prime is 21254789. The reversal of 21254730 is 3745212.

It is a self number, because there is not a number n which added to its sum of digits gives 21254730.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 27550 + ... + 28310.

It is an arithmetic number, because the mean of its divisors is an integer number (651510).

Almost surely, 2^21254730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21254730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31272480).

21254730 is an abundant number, since it is smaller than the sum of its proper divisors (41290230).

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

21254730 is a wasteful number, since it uses less digits than its factorization.

21254730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 804 (or 797 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 21254730 is about 4610.2852406332. The cubic root of 21254730 is about 277.0034623590.

Adding to 21254730 its reverse (3745212), we get a palindrome (24999942).

The spelling of 21254730 in words is "twenty-one million, two hundred fifty-four thousand, seven hundred thirty".