55721577 has 8 divisors (see below), whose sum is σ = 74331520. Its totient is φ = 37129680.

The previous prime is 55721569. The next prime is 55721579. The reversal of 55721577 is 77512755.

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

It is not a de Polignac number, because 55721577 - 2³ = 55721569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55721579) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6624 + ... + 12462.

It is an arithmetic number, because the mean of its divisors is an integer number (9291440).

Almost surely, 2^55721577 is an apocalyptic number.

It is an amenable number.

55721577 is a deficient number, since it is larger than the sum of its proper divisors (18609943).

55721577 is a wasteful number, since it uses less digits than its factorization.

55721577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9023.

The product of its digits is 85750, while the sum is 39.

The square root of 55721577 is about 7464.6886740172. The cubic root of 55721577 is about 381.9511304131.

The spelling of 55721577 in words is "fifty-five million, seven hundred twenty-one thousand, five hundred seventy-seven".