21683530 has 16 divisors (see below), whose sum is σ = 42578784. Its totient is φ = 7884880.

The previous prime is 21683509. The next prime is 21683531. The reversal of 21683530 is 3538612.

It is not an unprimeable number, because it can be changed into a prime (21683531) 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 7 ways as a sum of consecutive naturals, for example, 98452 + ... + 98671.

It is an arithmetic number, because the mean of its divisors is an integer number (2661174).

Almost surely, 2^21683530 is an apocalyptic number.

21683530 is a deficient number, since it is larger than the sum of its proper divisors (20895254).

21683530 is a wasteful number, since it uses less digits than its factorization.

21683530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197141.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 21683530 is about 4656.5577415082. The cubic root of 21683530 is about 278.8538607657.

The spelling of 21683530 in words is "twenty-one million, six hundred eighty-three thousand, five hundred thirty".