55711721 has 4 divisors (see below), whose sum is σ = 59997252. Its totient is φ = 51426192.

The previous prime is 55711687. The next prime is 55711739. The reversal of 55711721 is 12711755.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 35236096 + 20475625 = 5936^2 + 4525^2 .

It is a cyclic number.

It is not a de Polignac number, because 55711721 - 2⁶ = 55711657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55711741) 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, 2142746 + ... + 2142771.

It is an arithmetic number, because the mean of its divisors is an integer number (14999313).

Almost surely, 2^55711721 is an apocalyptic number.

It is an amenable number.

55711721 is a deficient number, since it is larger than the sum of its proper divisors (4285531).

55711721 is a wasteful number, since it uses less digits than its factorization.

55711721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4285530.

The product of its digits is 2450, while the sum is 29.

The square root of 55711721 is about 7464.0284699350. The cubic root of 55711721 is about 381.9286093209.

The spelling of 55711721 in words is "fifty-five million, seven hundred eleven thousand, seven hundred twenty-one".