57109991 has 8 divisors (see below), whose sum is σ = 61251120. Its totient is φ = 53082432.

The previous prime is 57109979. The next prime is 57109999. The reversal of 57109991 is 19990175.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-57109991 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 (57109999) 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, 27350 + ... + 29363.

It is an arithmetic number, because the mean of its divisors is an integer number (7656390).

Almost surely, 2^57109991 is an apocalyptic number.

57109991 is a deficient number, since it is larger than the sum of its proper divisors (4141129).

57109991 is a wasteful number, since it uses less digits than its factorization.

57109991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56785.

The product of its (nonzero) digits is 25515, while the sum is 41.

The square root of 57109991 is about 7557.1152564983. The cubic root of 57109991 is about 385.0974982173.

The spelling of 57109991 in words is "fifty-seven million, one hundred nine thousand, nine hundred ninety-one".