21221535303556 has 48 divisors (see below), whose sum is σ = 42472727178112. Its totient is φ = 9088590355200.

The previous prime is 21221535303541. The next prime is 21221535303571. The reversal of 21221535303556 is 65530353512212.

It is an interprime number because it is at equal distance from previous prime (21221535303541) and next prime (21221535303571).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 357590446 + ... + 357649786.

Almost surely, 2^{21221535303556} is an apocalyptic number.

It is an amenable number.

21221535303556 is an abundant number, since it is smaller than the sum of its proper divisors (21251191874556).

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

21221535303556 is a wasteful number, since it uses less digits than its factorization.

21221535303556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68060 (or 68058 counting only the distinct ones).

The product of its (nonzero) digits is 810000, while the sum is 43.

Adding to 21221535303556 its reverse (65530353512212), we get a palindrome (86751888815768).

The spelling of 21221535303556 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred thirty-five million, three hundred three thousand, five hundred fifty-six".