1021100001220 has 48 divisors (see below), whose sum is σ = 2309387473008. Its totient is φ = 377000225280.

The previous prime is 1021100001211. The next prime is 1021100001277. The reversal of 1021100001220 is 221000011201.

It can be written as a sum of positive squares in 8 ways, for example, as 18906800004 + 1002193201216 = 137502^2 + 1001096^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 1021100001197 and 1021100001206.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4937742 + ... + 5140378.

It is an arithmetic number, because the mean of its divisors is an integer number (48112239021).

Almost surely, 2^{1021100001220} is an apocalyptic number.

1021100001220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021100001220 is an abundant number, since it is smaller than the sum of its proper divisors (1288287471788).

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

1021100001220 is a wasteful number, since it uses less digits than its factorization.

1021100001220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222040 (or 222038 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 1021100001220 its reverse (221000011201), we get a palindrome (1242100012421).

The spelling of 1021100001220 in words is "one trillion, twenty-one billion, one hundred million, one thousand, two hundred twenty".