21331650 has 24 divisors (see below), whose sum is σ = 52902864. Its totient is φ = 5688400.

The previous prime is 21331643. The next prime is 21331657. The reversal of 21331650 is 5613312.

It is an interprime number because it is at equal distance from previous prime (21331643) and next prime (21331657).

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21331657) 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 11 ways as a sum of consecutive naturals, for example, 70956 + ... + 71255.

It is an arithmetic number, because the mean of its divisors is an integer number (2204286).

Almost surely, 2^21331650 is an apocalyptic number.

21331650 is an abundant number, since it is smaller than the sum of its proper divisors (31571214).

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

21331650 is a wasteful number, since it uses less digits than its factorization.

21331650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142226 (or 142221 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 21331650 is about 4618.6199237435. The cubic root of 21331650 is about 277.3372148100.

Adding to 21331650 its reverse (5613312), we get a palindrome (26944962).

The spelling of 21331650 in words is "twenty-one million, three hundred thirty-one thousand, six hundred fifty".