53728921 has 16 divisors (see below), whose sum is σ = 57541120. Its totient is φ = 50077440.

The previous prime is 53728907. The next prime is 53728933. The reversal of 53728921 is 12982735.

It is a 3-Lehmer number, since φ(53728921) divides (53728921-1)³.

It is a cyclic number.

It is not a de Polignac number, because 53728921 - 2⁵ = 53728889 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (53728981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159265 + ... + 159601.

It is an arithmetic number, because the mean of its divisors is an integer number (3596320).

It is a Poulet number, since it divides 2^53728920-1.

Almost surely, 2^53728921 is an apocalyptic number.

It is an amenable number.

53728921 is a deficient number, since it is larger than the sum of its proper divisors (3812199).

53728921 is a wasteful number, since it uses less digits than its factorization.

53728921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544.

The product of its digits is 30240, while the sum is 37.

The square root of 53728921 is about 7330.0014324692. The cubic root of 53728921 is about 377.3427756304.

The spelling of 53728921 in words is "fifty-three million, seven hundred twenty-eight thousand, nine hundred twenty-one".