820209660 has 48 divisors (see below), whose sum is σ = 2334246432. Its totient is φ = 215136000.

The previous prime is 820209623. The next prime is 820209661. The reversal of 820209660 is 66902028.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820209661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108391 + ... + 115710.

It is an arithmetic number, because the mean of its divisors is an integer number (48630134).

Almost surely, 2^820209660 is an apocalyptic number.

It is an amenable number.

820209660 is an abundant number, since it is smaller than the sum of its proper divisors (1514036772).

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

820209660 is a wasteful number, since it uses less digits than its factorization.

820209660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224174 (or 224172 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 820209660 is about 28639.3027149754. The cubic root of 820209660 is about 936.0699277510.

The spelling of 820209660 in words is "eight hundred twenty million, two hundred nine thousand, six hundred sixty".