820764 has 36 divisors (see below), whose sum is σ = 2371824. Its totient is φ = 234432.

The previous prime is 820763. The next prime is 820789. The reversal of 820764 is 467028.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820763) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1377 + ... + 1880.

It is an arithmetic number, because the mean of its divisors is an integer number (65884).

2⁸²⁰⁷⁶⁴ is an apocalyptic number.

820764 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

820764 is an abundant number, since it is smaller than the sum of its proper divisors (1551060).

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

820764 is a wasteful number, since it uses less digits than its factorization.

820764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3274 (or 3269 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 820764 is about 905.9602640293. The cubic root of 820764 is about 93.6280761709.

The spelling of 820764 in words is "eight hundred twenty thousand, seven hundred sixty-four".