21315650 has 24 divisors (see below), whose sum is σ = 39945360. Its totient is φ = 8462160.

The previous prime is 21315649. The next prime is 21315661. The reversal of 21315650 is 5651312.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5417 + ... + 8483.

It is an arithmetic number, because the mean of its divisors is an integer number (1664390).

Almost surely, 2^21315650 is an apocalyptic number.

21315650 is a deficient number, since it is larger than the sum of its proper divisors (18629710).

21315650 is a wasteful number, since it uses less digits than its factorization.

21315650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3218 (or 3213 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 21315650 is about 4616.8874796772. The cubic root of 21315650 is about 277.2678576914.

Adding to 21315650 its reverse (5651312), we get a palindrome (26966962).

The spelling of 21315650 in words is "twenty-one million, three hundred fifteen thousand, six hundred fifty".