55571391 has 6 divisors (see below), whose sum is σ = 80269800. Its totient is φ = 37047588.

The previous prime is 55571389. The next prime is 55571407. The reversal of 55571391 is 19317555.

55571391 is a `hidden beast` number, since 5 + 557 + 13 + 91 = 666.

It is not a de Polignac number, because 55571391 - 2¹ = 55571389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55571291) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3087291 + ... + 3087308.

It is an arithmetic number, because the mean of its divisors is an integer number (13378300).

Almost surely, 2^55571391 is an apocalyptic number.

55571391 is a deficient number, since it is larger than the sum of its proper divisors (24698409).

55571391 is a wasteful number, since it uses less digits than its factorization.

55571391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6174605 (or 6174602 counting only the distinct ones).

The product of its digits is 23625, while the sum is 36.

The square root of 55571391 is about 7454.6221232199. The cubic root of 55571391 is about 381.6076648580.

The spelling of 55571391 in words is "fifty-five million, five hundred seventy-one thousand, three hundred ninety-one".