57147991 has 4 divisors (see below), whose sum is σ = 60155800.
Its totient is φ = 54140184.
The previous prime is 57147983. The next prime is 57148019. The reversal of 57147991 is 19974175.
It is a semiprime because it is the product of two primes.
It is a cyclic number.
It is not a de Polignac number, because 57147991 - 23 = 57147983 is a prime.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (57147191) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1503876 + ... + 1503913.
It is an arithmetic number, because the mean of its divisors is an integer number (15038950).
Almost surely, 257147991 is an apocalyptic number.
57147991 is a deficient number, since it is larger than the sum of its proper divisors (3007809).
57147991 is a wasteful number, since it uses less digits than its factorization.
57147991 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 3007808.
The product of its digits is 79380, while the sum is 43.
The square root of 57147991 is about 7559.6290252895.
The cubic root of 57147991 is about 385.1828916846.
The spelling of 57147991 in words is "fifty-seven million, one hundred forty-seven thousand, nine hundred ninety-one".