820511646 has 16 divisors (see below), whose sum is σ = 1642944000. Its totient is φ = 273183768.

The previous prime is 820511623. The next prime is 820511693. The reversal of 820511646 is 646115028.

It is a super-2 number, since 2×820511646² = 1346478722443258632, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74446 + ... + 84753.

It is an arithmetic number, because the mean of its divisors is an integer number (102684000).

Almost surely, 2^820511646 is an apocalyptic number.

820511646 is an abundant number, since it is smaller than the sum of its proper divisors (822432354).

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

820511646 is a wasteful number, since it uses less digits than its factorization.

820511646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160063.

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 820511646 is about 28644.5744600963. The cubic root of 820511646 is about 936.1847948562.

The spelling of 820511646 in words is "eight hundred twenty million, five hundred eleven thousand, six hundred forty-six".