21144120 has 32 divisors (see below), whose sum is σ = 63432720. Its totient is φ = 5638400.

The previous prime is 21144119. The next prime is 21144121. The reversal of 21144120 is 2144112.

It is an interprime number because it is at equal distance from previous prime (21144119) and next prime (21144121).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21144120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87981 + ... + 88220.

Almost surely, 2^21144120 is an apocalyptic number.

21144120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21144120 is an abundant number, since it is smaller than the sum of its proper divisors (42288600).

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

21144120 is a wasteful number, since it uses less digits than its factorization.

21144120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176215 (or 176211 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 21144120 is about 4598.2735890767. The cubic root of 21144120 is about 276.5221160671.

Adding to 21144120 its reverse (2144112), we get a palindrome (23288232).

The spelling of 21144120 in words is "twenty-one million, one hundred forty-four thousand, one hundred twenty".