21121526551156 has 24 divisors (see below), whose sum is σ = 38238089881320. Its totient is φ = 10196374081152.

The previous prime is 21121526551109. The next prime is 21121526551267. The reversal of 21121526551156 is 65115562512112.

It can be written as a sum of positive squares in 4 ways, for example, as 12751441079056 + 8370085472100 = 3570916^2 + 2893110^2 .

It is a super-2 number, since 2×21121526551156² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 3333450 + ... + 7304446.

It is an arithmetic number, because the mean of its divisors is an integer number (1593253745055).

Almost surely, 2^{21121526551156} is an apocalyptic number.

It is an amenable number.

21121526551156 is a deficient number, since it is larger than the sum of its proper divisors (17116563330164).

21121526551156 is a wasteful number, since it uses less digits than its factorization.

21121526551156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4016883 (or 4016881 counting only the distinct ones).

The product of its digits is 180000, while the sum is 43.

The spelling of 21121526551156 in words is "twenty-one trillion, one hundred twenty-one billion, five hundred twenty-six million, five hundred fifty-one thousand, one hundred fifty-six".