100001021 has 16 divisors (see below), whose sum is σ = 109176048. Its totient is φ = 91238400.

The previous prime is 100000969. The next prime is 100001029. The reversal of 100001021 is 120100001.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 1792921 + 98208100 = 1339^2 + 9910^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100001021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 100000996 and 100001014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100001029) 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, 75041 + ... + 76361.

It is an arithmetic number, because the mean of its divisors is an integer number (6823503).

Almost surely, 2^100001021 is an apocalyptic number.

It is an amenable number.

100001021 is a deficient number, since it is larger than the sum of its proper divisors (9175027).

100001021 is a wasteful number, since it uses less digits than its factorization.

100001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1472.

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 100001021 is about 10000.0510498697. The cubic root of 100001021 is about 464.1604630433.

Adding to 100001021 its reverse (120100001), we get a palindrome (220101022).

The spelling of 100001021 in words is "one hundred million, one thousand, twenty-one".