57091891 has 4 divisors (see below), whose sum is σ = 57442312. Its totient is φ = 56741472.

The previous prime is 57091861. The next prime is 57091897. The reversal of 57091891 is 19819075.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-57091891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (57091897) 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, 174966 + ... + 175291.

It is an arithmetic number, because the mean of its divisors is an integer number (14360578).

Almost surely, 2^57091891 is an apocalyptic number.

57091891 is a deficient number, since it is larger than the sum of its proper divisors (350421).

57091891 is a wasteful number, since it uses less digits than its factorization.

57091891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350420.

The product of its (nonzero) digits is 22680, while the sum is 40.

The square root of 57091891 is about 7555.9176146912. The cubic root of 57091891 is about 385.0568106417.

The spelling of 57091891 in words is "fifty-seven million, ninety-one thousand, eight hundred ninety-one".