21556322 has 4 divisors (see below), whose sum is σ = 32334486. Its totient is φ = 10778160.

The previous prime is 21556321. The next prime is 21556349. The reversal of 21556322 is 22365512.

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., 20259001 + 1297321 = 4501^2 + 1139^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21556291 and 21556300.

It is not an unprimeable number, because it can be changed into a prime (21556321) 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, 5389079 + ... + 5389082.

Almost surely, 2^21556322 is an apocalyptic number.

21556322 is a deficient number, since it is larger than the sum of its proper divisors (10778164).

21556322 is a wasteful number, since it uses less digits than its factorization.

21556322 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10778163.

The product of its digits is 3600, while the sum is 26.

The square root of 21556322 is about 4642.8786329173. The cubic root of 21556322 is about 278.3074854583.

The spelling of 21556322 in words is "twenty-one million, five hundred fifty-six thousand, three hundred twenty-two".