21521500226556 has 36 divisors (see below), whose sum is σ = 55197015736296. Its totient is φ = 6521666734880.

The previous prime is 21521500226549. The next prime is 21521500226557. The reversal of 21521500226556 is 65562200512512.

It is a happy number.

It is a super-2 number, since 2×21521500226556² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521500226557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7410983475 + ... + 7410986378.

Almost surely, 2^{21521500226556} is an apocalyptic number.

It is an amenable number.

21521500226556 is an abundant number, since it is smaller than the sum of its proper divisors (33675515509740).

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

21521500226556 is a wasteful number, since it uses less digits than its factorization.

21521500226556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14821969882 (or 14821969869 counting only the distinct ones).

The product of its (nonzero) digits is 360000, while the sum is 42.

The spelling of 21521500226556 in words is "twenty-one trillion, five hundred twenty-one billion, five hundred million, two hundred twenty-six thousand, five hundred fifty-six".