21120030 has 48 divisors (see below), whose sum is σ = 55826784. Its totient is φ = 5538240.

The previous prime is 21120019. The next prime is 21120041. The reversal of 21120030 is 3002112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21120019) and next prime (21120041).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21119994 and 21120021.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3567 + ... + 7413.

It is an arithmetic number, because the mean of its divisors is an integer number (1163058).

Almost surely, 2^21120030 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21120030, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27913392).

21120030 is an abundant number, since it is smaller than the sum of its proper divisors (34706754).

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

21120030 is a wasteful number, since it uses less digits than its factorization.

21120030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3921 (or 3918 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 21120030 is about 4595.6533811853. The cubic root of 21120030 is about 276.4170600796.

Adding to 21120030 its reverse (3002112), we get a palindrome (24122142).

The spelling of 21120030 in words is "twenty-one million, one hundred twenty thousand, thirty".