65541632121 has 81 divisors (see below), whose sum is σ = 112329650511. Its totient is φ = 36718121664.

The previous prime is 65541632099. The next prime is 65541632161. The reversal of 65541632121 is 12123614556.

The square root of 65541632121 is 256011.

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

65541632121 is a `hidden beast` number, since 6 + 5 + 5 + 4 + 1 + 632 + 12 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 37204623225 + 28337008896 = 192885^2 + 168336^2 .

It is not a de Polignac number, because 65541632121 - 2¹⁷ = 65541501049 is a prime.

It is not an unprimeable number, because it can be changed into a prime (65541632161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 392464780 + ... + 392464946.

Almost surely, 2^65541632121 is an apocalyptic number.

65541632121 is the 256011-st square number.

65541632121 is the 128006-th centered octagonal number.

It is an amenable number.

65541632121 is a deficient number, since it is larger than the sum of its proper divisors (46788018390).

65541632121 is an equidigital number, since it uses as much as digits as its factorization.

65541632121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500 (or 250 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

Multiplying 65541632121 by its sum of digits (36), we get a square (2359498756356 = 1536066²).

The spelling of 65541632121 in words is "sixty-five billion, five hundred forty-one million, six hundred thirty-two thousand, one hundred twenty-one".