1011221221020 has 96 divisors (see below), whose sum is σ = 2911183220736. Its totient is φ = 262110988800.

The previous prime is 1011221220991. The next prime is 1011221221057. The reversal of 1011221221020 is 201221221101.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 91764 + ... + 1425083.

It is an arithmetic number, because the mean of its divisors is an integer number (30324825216).

Almost surely, 2^{1011221221020} is an apocalyptic number.

1011221221020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1011221221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1455591610368).

1011221221020 is an abundant number, since it is smaller than the sum of its proper divisors (1899961999716).

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

1011221221020 is a wasteful number, since it uses less digits than its factorization.

1011221221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1517171 (or 1517169 counting only the distinct ones).

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

Adding to 1011221221020 its reverse (201221221101), we get a palindrome (1212442442121).

The spelling of 1011221221020 in words is "one trillion, eleven billion, two hundred twenty-one million, two hundred twenty-one thousand, twenty".