117857821 has 8 divisors (see below), whose sum is σ = 127835064. Its totient is φ = 108218880.

The previous prime is 117857801. The next prime is 117857833. The reversal of 117857821 is 128758711.

It can be written as a sum of positive squares in 4 ways, for example, as 980100 + 116877721 = 990^2 + 10811^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 117857821 - 2⁷ = 117857693 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 (117857801) 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, 83850 + ... + 85243.

It is an arithmetic number, because the mean of its divisors is an integer number (15979383).

Almost surely, 2^117857821 is an apocalyptic number.

It is an amenable number.

117857821 is a deficient number, since it is larger than the sum of its proper divisors (9977243).

117857821 is a wasteful number, since it uses less digits than its factorization.

117857821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169151.

The product of its digits is 31360, while the sum is 40.

The square root of 117857821 is about 10856.2341997582. The cubic root of 117857821 is about 490.2897370162.

The spelling of 117857821 in words is "one hundred seventeen million, eight hundred fifty-seven thousand, eight hundred twenty-one".