21240030 has 48 divisors (see below), whose sum is σ = 59302800. Its totient is φ = 4854528.

The previous prime is 21240001. The next prime is 21240049. The reversal of 21240030 is 3004212.

It is a super-2 number, since 2×21240030² = 902277748801800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21239988 and 21240015.

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 23 ways as a sum of consecutive naturals, for example, 5755 + ... + 8694.

It is an arithmetic number, because the mean of its divisors is an integer number (1235475).

Almost surely, 2^21240030 is an apocalyptic number.

21240030 is an abundant number, since it is smaller than the sum of its proper divisors (38062770).

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

21240030 is a wasteful number, since it uses less digits than its factorization.

21240030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14473 (or 14466 counting only the distinct ones).

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

The square root of 21240030 is about 4608.6907034428. The cubic root of 21240030 is about 276.9395881062.

Adding to 21240030 its reverse (3004212), we get a palindrome (24244242).

The spelling of 21240030 in words is "twenty-one million, two hundred forty thousand, thirty".