817898945 has 4 divisors (see below), whose sum is σ = 981478740. Its totient is φ = 654319152.

The previous prime is 817898927. The next prime is 817898959. The reversal of 817898945 is 549898718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 549898718 = 2 ⋅274949359.

It can be written as a sum of positive squares in 2 ways, for example, as 216472369 + 601426576 = 14713^2 + 24524^2 .

It is a cyclic number.

It is not a de Polignac number, because 817898945 - 2⁶ = 817898881 is a prime.

It is a super-2 number, since 2×817898945² = 1337917368464226050, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81789890 + ... + 81789899.

It is an arithmetic number, because the mean of its divisors is an integer number (245369685).

Almost surely, 2^817898945 is an apocalyptic number.

It is an amenable number.

817898945 is a deficient number, since it is larger than the sum of its proper divisors (163579795).

817898945 is a wasteful number, since it uses less digits than its factorization.

817898945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163579794.

The product of its digits is 5806080, while the sum is 59.

The square root of 817898945 is about 28598.9325849760. The cubic root of 817898945 is about 935.1900611656.

The spelling of 817898945 in words is "eight hundred seventeen million, eight hundred ninety-eight thousand, nine hundred forty-five".