21328131461121 has 27 divisors (see below), whose sum is σ = 32205466906977. Its totient is φ = 13600344395880.

The previous prime is 21328131461071. The next prime is 21328131461129. The reversal of 21328131461121 is 12116413182312.

The square root of 21328131461121 is 4618239.

It is a perfect power (a square), and thus also a powerful number.

21328131461121 is a `hidden beast` number, since 2 + 1 + 3 + 2 + 8 + 1 + 3 + 14 + 611 + 21 = 666.

It is not a de Polignac number, because 21328131461121 - 2¹¹ = 21328131459073 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21328131461129) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 318625026 + ... + 318691956.

Almost surely, 2^{21328131461121} is an apocalyptic number.

21328131461121 is the 4618239-th square number.

21328131461121 is the 2309120-th centered octagonal number.

It is an amenable number.

21328131461121 is a deficient number, since it is larger than the sum of its proper divisors (10877335445856).

21328131461121 is an frugal number, since it uses more digits than its factorization.

21328131461121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133914 (or 66957 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

Multiplying 21328131461121 by its sum of digits (36), we get a square (767812732600356 = 27709434²).

The spelling of 21328131461121 in words is "twenty-one trillion, three hundred twenty-eight billion, one hundred thirty-one million, four hundred sixty-one thousand, one hundred twenty-one".