21665362 has 4 divisors (see below), whose sum is σ = 32498046. Its totient is φ = 10832680.

The previous prime is 21665353. The next prime is 21665363. The reversal of 21665362 is 26356612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 13830961 + 7834401 = 3719^2 + 2799^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21665363) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5416339 + ... + 5416342.

Almost surely, 2^21665362 is an apocalyptic number.

21665362 is a deficient number, since it is larger than the sum of its proper divisors (10832684).

21665362 is a wasteful number, since it uses less digits than its factorization.

21665362 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10832683.

The product of its digits is 12960, while the sum is 31.

The square root of 21665362 is about 4654.6065354657. The cubic root of 21665362 is about 278.7759578205.

The spelling of 21665362 in words is "twenty-one million, six hundred sixty-five thousand, three hundred sixty-two".