53721665 has 8 divisors (see below), whose sum is σ = 64559040. Its totient is φ = 42915312.

The previous prime is 53721641. The next prime is 53721671. The reversal of 53721665 is 56612735.

53721665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-53721665 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3755 + ... + 11024.

It is an arithmetic number, because the mean of its divisors is an integer number (8069880).

Almost surely, 2^53721665 is an apocalyptic number.

It is an amenable number.

53721665 is a deficient number, since it is larger than the sum of its proper divisors (10837375).

53721665 is a wasteful number, since it uses less digits than its factorization.

53721665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15511.

The product of its digits is 37800, while the sum is 35.

The square root of 53721665 is about 7329.5064636031. The cubic root of 53721665 is about 377.3257883643.

The spelling of 53721665 in words is "fifty-three million, seven hundred twenty-one thousand, six hundred sixty-five".