21042030 has 16 divisors (see below), whose sum is σ = 50500944. Its totient is φ = 5611200.

The previous prime is 21042017. The next prime is 21042053. The reversal of 21042030 is 3024012.

It is a junction number, because it is equal to n+sod(n) for n = 21041997 and 21042015.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 350671 + ... + 350730.

It is an arithmetic number, because the mean of its divisors is an integer number (3156309).

Almost surely, 2^21042030 is an apocalyptic number.

21042030 is an abundant number, since it is smaller than the sum of its proper divisors (29458914).

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

21042030 is a wasteful number, since it uses less digits than its factorization.

21042030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701411.

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

The square root of 21042030 is about 4587.1592516502. The cubic root of 21042030 is about 276.0763546361.

Adding to 21042030 its reverse (3024012), we get a palindrome (24066042).

The spelling of 21042030 in words is "twenty-one million, forty-two thousand, thirty".