53181621 has 12 divisors (see below), whose sum is σ = 79467180. Its totient is φ = 34231680.

The previous prime is 53181607. The next prime is 53181641. The reversal of 53181621 is 12618135.

53181621 is a `hidden beast` number, since 5 + 31 + 8 + 1 + 621 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15800625 + 37380996 = 3975^2 + 6114^2 .

It is not a de Polignac number, because 53181621 - 2¹⁰ = 53180597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (53181641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 101620 + ... + 102141.

It is an arithmetic number, because the mean of its divisors is an integer number (6622265).

Almost surely, 2^53181621 is an apocalyptic number.

It is an amenable number.

53181621 is a deficient number, since it is larger than the sum of its proper divisors (26285559).

53181621 is a wasteful number, since it uses less digits than its factorization.

53181621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203796 (or 203793 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 53181621 is about 7292.5730027200. The cubic root of 53181621 is about 376.0571556580.

Adding to 53181621 its reverse (12618135), we get a palindrome (65799756).

The spelling of 53181621 in words is "fifty-three million, one hundred eighty-one thousand, six hundred twenty-one".