813487561 has 4 divisors (see below), whose sum is σ = 818358912. Its totient is φ = 808616212.

The previous prime is 813487531. The next prime is 813487567. The reversal of 813487561 is 165784318.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 813487561 - 2⁹ = 813487049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (813487567) 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, 2435425 + ... + 2435758.

It is an arithmetic number, because the mean of its divisors is an integer number (204589728).

Almost surely, 2^813487561 is an apocalyptic number.

It is an amenable number.

813487561 is a deficient number, since it is larger than the sum of its proper divisors (4871351).

813487561 is a wasteful number, since it uses less digits than its factorization.

813487561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4871350.

The product of its digits is 161280, while the sum is 43.

The square root of 813487561 is about 28521.7033327254. The cubic root of 813487561 is about 933.5056958741.

The spelling of 813487561 in words is "eight hundred thirteen million, four hundred eighty-seven thousand, five hundred sixty-one".