21120550 has 36 divisors (see below), whose sum is σ = 43192548. Its totient is φ = 7678000.

The previous prime is 21120523. The next prime is 21120551. The reversal of 21120550 is 5502112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120551) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4305 + ... + 7795.

It is an arithmetic number, because the mean of its divisors is an integer number (1199793).

Almost surely, 2^21120550 is an apocalyptic number.

21120550 is an abundant number, since it is smaller than the sum of its proper divisors (22071998).

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

21120550 is a wasteful number, since it uses less digits than its factorization.

21120550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3525 (or 3509 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 21120550 is about 4595.7099560351. The cubic root of 21120550 is about 276.4193286321.

Adding to 21120550 its reverse (5502112), we get a palindrome (26622662).

The spelling of 21120550 in words is "twenty-one million, one hundred twenty thousand, five hundred fifty".