21780150 has 48 divisors (see below), whose sum is σ = 61734144. Its totient is φ = 4978080.

The previous prime is 21780133. The next prime is 21780151. The reversal of 21780150 is 5108712.

It is a self number, because there is not a number n which added to its sum of digits gives 21780150.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21780151) 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 23 ways as a sum of consecutive naturals, for example, 9322 + ... + 11421.

It is an arithmetic number, because the mean of its divisors is an integer number (1286128).

Almost surely, 2^21780150 is an apocalyptic number.

21780150 is an abundant number, since it is smaller than the sum of its proper divisors (39953994).

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

21780150 is a wasteful number, since it uses less digits than its factorization.

21780150 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20765 (or 20760 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 24.

The square root of 21780150 is about 4666.9208264122. The cubic root of 21780150 is about 279.2674302724.

Adding to 21780150 its reverse (5108712), we get a palindrome (26888862).

The spelling of 21780150 in words is "twenty-one million, seven hundred eighty thousand, one hundred fifty".