21225830 has 16 divisors (see below), whose sum is σ = 38409984. Its totient is φ = 8445120.

The previous prime is 21225817. The next prime is 21225833. The reversal of 21225830 is 3852212.

It is a junction number, because it is equal to n+sod(n) for n = 21225796 and 21225805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225833) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3647 + ... + 7466.

It is an arithmetic number, because the mean of its divisors is an integer number (2400624).

Almost surely, 2^21225830 is an apocalyptic number.

21225830 is a deficient number, since it is larger than the sum of its proper divisors (17184154).

21225830 is a wasteful number, since it uses less digits than its factorization.

21225830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11311.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21225830 is about 4607.1498781785. The cubic root of 21225830 is about 276.8778584564.

The spelling of 21225830 in words is "twenty-one million, two hundred twenty-five thousand, eight hundred thirty".