21120750 has 160 divisors (see below), whose sum is σ = 67953600. Its totient is φ = 4795200.

The previous prime is 21120733. The next prime is 21120763. The reversal of 21120750 is 5702112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 141676 + ... + 141824.

It is an arithmetic number, because the mean of its divisors is an integer number (424710).

Almost surely, 2^21120750 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21120750, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33976800).

21120750 is an abundant number, since it is smaller than the sum of its proper divisors (46832850).

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

21120750 is a wasteful number, since it uses less digits than its factorization.

21120750 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185 (or 166 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21120750 is about 4595.7317154072. The cubic root of 21120750 is about 276.4202011424.

Adding to 21120750 its reverse (5702112), we get a palindrome (26822862).

The spelling of 21120750 in words is "twenty-one million, one hundred twenty thousand, seven hundred fifty".