21321650 has 24 divisors (see below), whose sum is σ = 45324480. Its totient is φ = 7310160.

The previous prime is 21321647. The next prime is 21321661. The reversal of 21321650 is 5612312.

It is a super-2 number, since 2×21321650² = 909225517445000, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

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, 30110 + ... + 30809.

It is an arithmetic number, because the mean of its divisors is an integer number (1888520).

Almost surely, 2^21321650 is an apocalyptic number.

21321650 is an abundant number, since it is smaller than the sum of its proper divisors (24002830).

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

21321650 is a wasteful number, since it uses less digits than its factorization.

21321650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60938 (or 60933 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21321650 is about 4617.5372223730. The cubic root of 21321650 is about 277.2938706768.

Adding to 21321650 its reverse (5612312), we get a palindrome (26933962).

It can be divided in two parts, 21 and 321650, that multiplied together give a triangular number (6754650 = T₃₆₇₅).

The spelling of 21321650 in words is "twenty-one million, three hundred twenty-one thousand, six hundred fifty".