55653999921 has 81 divisors (see below), whose sum is σ = 91345152171. Its totient is φ = 32634984096.

The previous prime is 55653999911. The next prime is 55653999959. The reversal of 55653999921 is 12999935655.

The square root of 55653999921 is 235911.

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

55653999921 is a `hidden beast` number, since 5 + 5 + 6 + 539 + 9 + 9 + 92 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 8232840225 + 47421159696 = 90735^2 + 217764^2 .

It is not a de Polignac number, because 55653999921 - 2²¹ = 55651902769 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (55653999901) 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, 211612036 + ... + 211612298.

Almost surely, 2^55653999921 is an apocalyptic number.

55653999921 is the 235911-st square number.

55653999921 is the 117956-th centered octagonal number.

It is an amenable number.

55653999921 is a deficient number, since it is larger than the sum of its proper divisors (35691152250).

55653999921 is a wasteful number, since it uses less digits than its factorization.

55653999921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 604 (or 302 counting only the distinct ones).

The product of its digits is 29524500, while the sum is 63.

The spelling of 55653999921 in words is "fifty-five billion, six hundred fifty-three million, nine hundred ninety-nine thousand, nine hundred twenty-one".