813977 has 4 divisors (see below), whose sum is σ = 861876. Its totient is φ = 766080.

The previous prime is 813971. The next prime is 813991. The reversal of 813977 is 779318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 779318 = 2 ⋅389659.

It can be written as a sum of positive squares in 2 ways, for example, as 687241 + 126736 = 829^2 + 356^2 .

It is a cyclic number.

It is not a de Polignac number, because 813977 - 2⁴ = 813961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (813971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23924 + ... + 23957.

It is an arithmetic number, because the mean of its divisors is an integer number (215469).

2⁸¹³⁹⁷⁷ is an apocalyptic number.

It is an amenable number.

813977 is a deficient number, since it is larger than the sum of its proper divisors (47899).

813977 is a wasteful number, since it uses less digits than its factorization.

813977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47898.

The product of its digits is 10584, while the sum is 35.

The square root of 813977 is about 902.2067390571. The cubic root of 813977 is about 93.3692874517.

The spelling of 813977 in words is "eight hundred thirteen thousand, nine hundred seventy-seven".