53856721 has 4 divisors (see below), whose sum is σ = 53922672. Its totient is φ = 53790772.

The previous prime is 53856707. The next prime is 53856727. The reversal of 53856721 is 12765835.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 53856721 - 2¹⁵ = 53823953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (53856727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31735 + ... + 33388.

It is an arithmetic number, because the mean of its divisors is an integer number (13480668).

Almost surely, 2^53856721 is an apocalyptic number.

It is an amenable number.

53856721 is a deficient number, since it is larger than the sum of its proper divisors (65951).

53856721 is an equidigital number, since it uses as much as digits as its factorization.

53856721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65950.

The product of its digits is 50400, while the sum is 37.

The square root of 53856721 is about 7338.7138518953. The cubic root of 53856721 is about 377.6417221483.

The spelling of 53856721 in words is "fifty-three million, eight hundred fifty-six thousand, seven hundred twenty-one".