815221117 has 8 divisors (see below), whose sum is σ = 845107200. Its totient is φ = 785453424.

The previous prime is 815221109. The next prime is 815221159. The reversal of 815221117 is 711122518.

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 815221117 - 2³ = 815221109 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 (815221217) 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, 15453 + ... + 43234.

It is an arithmetic number, because the mean of its divisors is an integer number (105638400).

Almost surely, 2^815221117 is an apocalyptic number.

It is an amenable number.

815221117 is a deficient number, since it is larger than the sum of its proper divisors (29886083).

815221117 is a wasteful number, since it uses less digits than its factorization.

815221117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59195.

The product of its digits is 1120, while the sum is 28.

The square root of 815221117 is about 28552.0772799458. The cubic root of 815221117 is about 934.1683309718.

The spelling of 815221117 in words is "eight hundred fifteen million, two hundred twenty-one thousand, one hundred seventeen".