1001121020 has 48 divisors (see below), whose sum is σ = 2249335200. Its totient is φ = 373144320.

The previous prime is 1001120999. The next prime is 1001121031. The reversal of 1001121020 is 201211001.

It is a junction number, because it is equal to n+sod(n) for n = 1001120989 and 1001121007.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1586 + ... + 44774.

It is an arithmetic number, because the mean of its divisors is an integer number (46861150).

Almost surely, 2^1001121020 is an apocalyptic number.

1001121020 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 1001121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1124667600).

1001121020 is an abundant number, since it is smaller than the sum of its proper divisors (1248214180).

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

1001121020 is a wasteful number, since it uses less digits than its factorization.

1001121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43278 (or 43276 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 1001121020 is about 31640.4965194922. The cubic root of 1001121020 is about 1000.3735337885.

Adding to 1001121020 its reverse (201211001), we get a palindrome (1202332021).

The spelling of 1001121020 in words is "one billion, one million, one hundred twenty-one thousand, twenty".