811918645 has 8 divisors (see below), whose sum is σ = 974587320. Its totient is φ = 649344960.

The previous prime is 811918643. The next prime is 811918649. The reversal of 811918645 is 546819118.

It can be written as a sum of positive squares in 4 ways, for example, as 217680516 + 594238129 = 14754^2 + 24377^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 811918645 - 2¹ = 811918643 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811918643) 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, 3346 + ... + 40435.

It is an arithmetic number, because the mean of its divisors is an integer number (121823415).

Almost surely, 2^811918645 is an apocalyptic number.

It is an amenable number.

811918645 is a deficient number, since it is larger than the sum of its proper divisors (162668675).

811918645 is a wasteful number, since it uses less digits than its factorization.

811918645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47495.

The product of its digits is 69120, while the sum is 43.

The square root of 811918645 is about 28494.1861613909. The cubic root of 811918645 is about 932.9051808183.

The spelling of 811918645 in words is "eight hundred eleven million, nine hundred eighteen thousand, six hundred forty-five".