102821100 has 72 divisors (see below), whose sum is σ = 315011088. Its totient is φ = 25804800.

The previous prime is 102821057. The next prime is 102821123. The reversal of 102821100 is 1128201.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 102821100.

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 23 ways as a sum of consecutive naturals, for example, 4981 + ... + 15180.

It is an arithmetic number, because the mean of its divisors is an integer number (4375154).

Almost surely, 2^102821100 is an apocalyptic number.

102821100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

102821100 is an abundant number, since it is smaller than the sum of its proper divisors (212189988).

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

102821100 is a wasteful number, since it uses less digits than its factorization.

102821100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20195 (or 20188 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

The square root of 102821100 is about 10140.0739642273. The cubic root of 102821100 is about 468.4832651364.

Adding to 102821100 its reverse (1128201), we get a palindrome (103949301).

The spelling of 102821100 in words is "one hundred two million, eight hundred twenty-one thousand, one hundred".