21765150 has 72 divisors (see below), whose sum is σ = 63806184. Its totient is φ = 5275200.

The previous prime is 21765119. The next prime is 21765157. The reversal of 21765150 is 5156712.

21765150 is a `hidden beast` number, since 2 + 1 + 7 + 651 + 5 + 0 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21765157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2752 + ... + 7148.

It is an arithmetic number, because the mean of its divisors is an integer number (886197).

Almost surely, 2^21765150 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21765150, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31903092).

21765150 is an abundant number, since it is smaller than the sum of its proper divisors (42041034).

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

21765150 is a wasteful number, since it uses less digits than its factorization.

21765150 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4426 (or 4418 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The square root of 21765150 is about 4665.3134942895. The cubic root of 21765150 is about 279.2033050104.

The spelling of 21765150 in words is "twenty-one million, seven hundred sixty-five thousand, one hundred fifty".