820644499990 has 64 divisors (see below), whose sum is σ = 1704904980480. Its totient is φ = 278577895680.

The previous prime is 820644499981. The next prime is 820644500041. The reversal of 820644499990 is 99994446028.

It is a super-2 number, since 2×820644499990² (a number of 25 digits) 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 (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 58314655 + ... + 58328725.

It is an arithmetic number, because the mean of its divisors is an integer number (26639140320).

Almost surely, 2^820644499990 is an apocalyptic number.

820644499990 is an abundant number, since it is smaller than the sum of its proper divisors (884260480490).

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

820644499990 is a wasteful number, since it uses less digits than its factorization.

820644499990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22277.

The product of its (nonzero) digits is 40310784, while the sum is 64.

The spelling of 820644499990 in words is "eight hundred twenty billion, six hundred forty-four million, four hundred ninety-nine thousand, nine hundred ninety".