21420030 has 32 divisors (see below), whose sum is σ = 54115200. Its totient is φ = 5411232.

The previous prime is 21420023. The next prime is 21420031. The reversal of 21420030 is 3002412.

It is a junction number, because it is equal to n+sod(n) for n = 21419988 and 21420015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18220 + ... + 19359.

It is an arithmetic number, because the mean of its divisors is an integer number (1691100).

Almost surely, 2^21420030 is an apocalyptic number.

21420030 is an abundant number, since it is smaller than the sum of its proper divisors (32695170).

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

21420030 is a wasteful number, since it uses less digits than its factorization.

21420030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37608.

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 21420030 is about 4628.1778271799. The cubic root of 21420030 is about 277.7197026442.

Adding to 21420030 its reverse (3002412), we get a palindrome (24422442).

The spelling of 21420030 in words is "twenty-one million, four hundred twenty thousand, thirty".