813990 has 32 divisors (see below), whose sum is σ = 2002176. Its totient is φ = 211680.

The previous prime is 813971. The next prime is 813991. The reversal of 813990 is 99318.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is a plaindrome in base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 813990.

It is not an unprimeable number, because it can be changed into a prime (813991) 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 15 ways as a sum of consecutive naturals, for example, 975 + ... + 1605.

It is an arithmetic number, because the mean of its divisors is an integer number (62568).

2⁸¹³⁹⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 813990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1001088).

813990 is an abundant number, since it is smaller than the sum of its proper divisors (1188186).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

813990 is a wasteful number, since it uses less digits than its factorization.

813990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 684.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 813990 is about 902.2139435854. The cubic root of 813990 is about 93.3697845150.

The spelling of 813990 in words is "eight hundred thirteen thousand, nine hundred ninety".