813193985 has 4 divisors (see below), whose sum is σ = 975832788. Its totient is φ = 650555184.

The previous prime is 813193981. The next prime is 813194059. The reversal of 813193985 is 589391318.

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 130051216 + 683142769 = 11404^2 + 26137^2 .

It is a cyclic number.

It is not a de Polignac number, because 813193985 - 2² = 813193981 is a prime.

It is a super-2 number, since 2×813193985² = 1322568914480360450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (813193981) 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, 81319394 + ... + 81319403.

It is an arithmetic number, because the mean of its divisors is an integer number (243958197).

Almost surely, 2^813193985 is an apocalyptic number.

It is an amenable number.

813193985 is a deficient number, since it is larger than the sum of its proper divisors (162638803).

813193985 is a wasteful number, since it uses less digits than its factorization.

813193985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162638802.

The product of its digits is 233280, while the sum is 47.

The square root of 813193985 is about 28516.5563313665. The cubic root of 813193985 is about 933.3933860878.

The spelling of 813193985 in words is "eight hundred thirteen million, one hundred ninety-three thousand, nine hundred eighty-five".