1040001021 has 12 divisors (see below), whose sum is σ = 1509851772. Its totient is φ = 689813376.

The previous prime is 1040000999. The next prime is 1040001023. The reversal of 1040001021 is 1201000401.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 556440921 + 483560100 = 23589^2 + 21990^2 .

It is not a de Polignac number, because 1040001021 - 2⁷ = 1040000893 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 = 1040000994 and 1040001012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1040001023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 291516 + ... + 295061.

It is an arithmetic number, because the mean of its divisors is an integer number (125820981).

Almost surely, 2^1040001021 is an apocalyptic number.

It is an amenable number.

1040001021 is a deficient number, since it is larger than the sum of its proper divisors (469850751).

1040001021 is a wasteful number, since it uses less digits than its factorization.

1040001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586780 (or 586777 counting only the distinct ones).

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

The square root of 1040001021 is about 32249.0468231233. The cubic root of 1040001021 is about 1013.1597353700.

Adding to 1040001021 its reverse (1201000401), we get a palindrome (2241001422).

The spelling of 1040001021 in words is "one billion, forty million, one thousand, twenty-one".