818817121 has 4 divisors (see below), whose sum is σ = 866982852. Its totient is φ = 770651392.

The previous prime is 818817113. The next prime is 818817149. The reversal of 818817121 is 121718818.

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 347449600 + 471367521 = 18640^2 + 21711^2 .

It is a cyclic number.

It is not a de Polignac number, because 818817121 - 2³ = 818817113 is a prime.

It is a super-2 number, since 2×818817121² = 1340922955285457282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (818817151) 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, 24082840 + ... + 24082873.

It is an arithmetic number, because the mean of its divisors is an integer number (216745713).

Almost surely, 2^818817121 is an apocalyptic number.

It is an amenable number.

818817121 is a deficient number, since it is larger than the sum of its proper divisors (48165731).

818817121 is a wasteful number, since it uses less digits than its factorization.

818817121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48165730.

The product of its digits is 7168, while the sum is 37.

The square root of 818817121 is about 28614.9807094116. The cubic root of 818817121 is about 935.5398794246.

The spelling of 818817121 in words is "eight hundred eighteen million, eight hundred seventeen thousand, one hundred twenty-one".