1001221011 has 24 divisors (see below), whose sum is σ = 1654165344. Its totient is φ = 571656960.

The previous prime is 1001220991. The next prime is 1001221021. The reversal of 1001221011 is 1101221001.

It is a happy number.

It is not a de Polignac number, because 1001221011 - 2⁶ = 1001220947 is a prime.

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 = 1001220984 and 1001221002.

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 23 ways as a sum of consecutive naturals, for example, 79905 + ... + 91581.

It is an arithmetic number, because the mean of its divisors is an integer number (68923556).

Almost surely, 2^1001221011 is an apocalyptic number.

1001221011 is a deficient number, since it is larger than the sum of its proper divisors (652944333).

1001221011 is a wasteful number, since it uses less digits than its factorization.

1001221011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13051 (or 13048 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 1001221011 is about 31642.0765911468. The cubic root of 1001221011 is about 1000.4068381270.

Adding to 1001221011 its reverse (1101221001), we get a palindrome (2102442012).

The spelling of 1001221011 in words is "one billion, one million, two hundred twenty-one thousand, eleven".