819152561 has 4 divisors (see below), whose sum is σ = 819934500. Its totient is φ = 818370624.

The previous prime is 819152539. The next prime is 819152611. The reversal of 819152561 is 165251918.

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 452200225 + 366952336 = 21265^2 + 19156^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-819152561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (819152461) 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, 389396 + ... + 391493.

It is an arithmetic number, because the mean of its divisors is an integer number (204983625).

Almost surely, 2^819152561 is an apocalyptic number.

It is an amenable number.

819152561 is a deficient number, since it is larger than the sum of its proper divisors (781939).

819152561 is a wasteful number, since it uses less digits than its factorization.

819152561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781938.

The product of its digits is 21600, while the sum is 38.

The square root of 819152561 is about 28620.8413747744. The cubic root of 819152561 is about 935.6676143590.

The spelling of 819152561 in words is "eight hundred nineteen million, one hundred fifty-two thousand, five hundred sixty-one".