21133750 has 80 divisors (see below), whose sum is σ = 45547920. Its totient is φ = 7280000.

The previous prime is 21133747. The next prime is 21133753. The reversal of 21133750 is 5733112.

It is an interprime number because it is at equal distance from previous prime (21133747) and next prime (21133753).

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 398724 + ... + 398776.

It is an arithmetic number, because the mean of its divisors is an integer number (569349).

Almost surely, 2^21133750 is an apocalyptic number.

21133750 is an abundant number, since it is smaller than the sum of its proper divisors (24414170).

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

21133750 is a wasteful number, since it uses less digits than its factorization.

21133750 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 630, while the sum is 22.

The square root of 21133750 is about 4597.1458536792. The cubic root of 21133750 is about 276.4769025001.

Adding to 21133750 its reverse (5733112), we get a palindrome (26866862).

The spelling of 21133750 in words is "twenty-one million, one hundred thirty-three thousand, seven hundred fifty".