1001221020 has 48 divisors (see below), whose sum is σ = 3114911520. Its totient is φ = 266992128.

The previous prime is 1001220991. The next prime is 1001221021. The reversal of 1001221020 is 201221001.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 1001220993 and 1001221011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001221021) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 926517 + ... + 927596.

It is an arithmetic number, because the mean of its divisors is an integer number (64893990).

Almost surely, 2^1001221020 is an apocalyptic number.

1001221020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1001221020 is an abundant number, since it is smaller than the sum of its proper divisors (2113690500).

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

1001221020 is a wasteful number, since it uses less digits than its factorization.

1001221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1854131 (or 1854123 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1001221020 is about 31642.0767333625. The cubic root of 1001221020 is about 1000.4068411245.

Adding to 1001221020 its reverse (201221001), we get a palindrome (1202442021).

The spelling of 1001221020 in words is "one billion, one million, two hundred twenty-one thousand, twenty".