1001120021 has 32 divisors (see below), whose sum is σ = 1193367168. Its totient is φ = 829603840.

The previous prime is 1001120009. The next prime is 1001120039. The reversal of 1001120021 is 1200211001.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001120021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1001119990 and 1001120008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001120041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 822005 + ... + 823221.

It is an arithmetic number, because the mean of its divisors is an integer number (37292724).

Almost surely, 2^1001120021 is an apocalyptic number.

1001120021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1001120021 is a deficient number, since it is larger than the sum of its proper divisors (192247147).

1001120021 is a wasteful number, since it uses less digits than its factorization.

1001120021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1381.

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

The square root of 1001120021 is about 31640.4807327575. The cubic root of 1001120021 is about 1000.3732010370.

Adding to 1001120021 its reverse (1200211001), we get a palindrome (2201331022).

It can be divided in two parts, 10011 and 20021, that multiplied together give a triangular number (200430231 = T₂₀₀₂₁).

The spelling of 1001120021 in words is "one billion, one million, one hundred twenty thousand, twenty-one".