21123030 has 16 divisors (see below), whose sum is σ = 50695344. Its totient is φ = 5632800.

The previous prime is 21123029. The next prime is 21123043. The reversal of 21123030 is 3032112.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21122997 and 21123015.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 352021 + ... + 352080.

It is an arithmetic number, because the mean of its divisors is an integer number (3168459).

Almost surely, 2^21123030 is an apocalyptic number.

21123030 is an abundant number, since it is smaller than the sum of its proper divisors (29572314).

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

21123030 is a wasteful number, since it uses less digits than its factorization.

21123030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704111.

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

The square root of 21123030 is about 4595.9797649685. The cubic root of 21123030 is about 276.4301473704.

Adding to 21123030 its reverse (3032112), we get a palindrome (24155142).

The spelling of 21123030 in words is "twenty-one million, one hundred twenty-three thousand, thirty".