819121918 has 16 divisors (see below), whose sum is σ = 1242242496. Its totient is φ = 405050400.

The previous prime is 819121883. The next prime is 819121949.

819121918 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 243355 + ... + 246697.

It is an arithmetic number, because the mean of its divisors is an integer number (77640156).

Almost surely, 2^819121918 is an apocalyptic number.

819121918 is a deficient number, since it is larger than the sum of its proper divisors (423120578).

819121918 is a wasteful number, since it uses less digits than its factorization.

819121918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4659.

The product of its digits is 10368, while the sum is 40.

The square root of 819121918 is about 28620.3060430877. The cubic root of 819121918 is about 935.6559470084.

The spelling of 819121918 in words is "eight hundred nineteen million, one hundred twenty-one thousand, nine hundred eighteen".