117216521 has 4 divisors (see below), whose sum is σ = 121258500. Its totient is φ = 113174544.

The previous prime is 117216511. The next prime is 117216523. The reversal of 117216521 is 125612711.

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

It can be written as a sum of positive squares in 2 ways, for example, as 99281296 + 17935225 = 9964^2 + 4235^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-117216521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (117216523) 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, 2020946 + ... + 2021003.

It is an arithmetic number, because the mean of its divisors is an integer number (30314625).

Almost surely, 2^117216521 is an apocalyptic number.

It is an amenable number.

117216521 is a deficient number, since it is larger than the sum of its proper divisors (4041979).

117216521 is an equidigital number, since it uses as much as digits as its factorization.

117216521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4041978.

The product of its digits is 840, while the sum is 26.

The square root of 117216521 is about 10826.6578869012. The cubic root of 117216521 is about 489.3988476782.

The spelling of 117216521 in words is "one hundred seventeen million, two hundred sixteen thousand, five hundred twenty-one".