1021221121020 has 96 divisors (see below), whose sum is σ = 2939971700736. Its totient is φ = 264702988800.

The previous prime is 1021221120883. The next prime is 1021221121049. The reversal of 1021221121020 is 201211221201.

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, 99264 + ... + 1432583.

It is an arithmetic number, because the mean of its divisors is an integer number (30624705216).

Almost surely, 2^{1021221121020} is an apocalyptic number.

1021221121020 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 1021221121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1469985850368).

1021221121020 is an abundant number, since it is smaller than the sum of its proper divisors (1918750579716).

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

1021221121020 is a wasteful number, since it uses less digits than its factorization.

1021221121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1532171 (or 1532169 counting only the distinct ones).

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

Adding to 1021221121020 its reverse (201211221201), we get a palindrome (1222432342221).

The spelling of 1021221121020 in words is "one trillion, twenty-one billion, two hundred twenty-one million, one hundred twenty-one thousand, twenty".