1021200120020 has 24 divisors (see below), whose sum is σ = 2173897244904. Its totient is φ = 402884430336.

The previous prime is 1021200120019. The next prime is 1021200120071. The reversal of 1021200120020 is 200210021201.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 378567017284 + 642633102736 = 615278^2 + 801644^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1021200119983 and 1021200120010.

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 7 ways as a sum of consecutive naturals, for example, 349724609 + ... + 349727528.

It is an arithmetic number, because the mean of its divisors is an integer number (90579051871).

Almost surely, 2^{1021200120020} is an apocalyptic number.

1021200120020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021200120020 is an abundant number, since it is smaller than the sum of its proper divisors (1152697124884).

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

1021200120020 is a wasteful number, since it uses less digits than its factorization.

1021200120020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 699452219 (or 699452217 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 1021200120020 its reverse (200210021201), we get a palindrome (1221410141221).

The spelling of 1021200120020 in words is "one trillion, twenty-one billion, two hundred million, one hundred twenty thousand, twenty".