1001201021 has 4 divisors (see below), whose sum is σ = 1001595132. Its totient is φ = 1000806912.

The previous prime is 1001200999. The next prime is 1001201027. The reversal of 1001201021 is 1201021001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1201021001 = 163 ⋅7368227.

It can be written as a sum of positive squares in 2 ways, for example, as 611572900 + 389628121 = 24730^2 + 19739^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001201021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001201027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 193220 + ... + 198333.

It is an arithmetic number, because the mean of its divisors is an integer number (250398783).

Almost surely, 2^1001201021 is an apocalyptic number.

It is an amenable number.

1001201021 is a deficient number, since it is larger than the sum of its proper divisors (394111).

1001201021 is an equidigital number, since it uses as much as digits as its factorization.

1001201021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394110.

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

The square root of 1001201021 is about 31641.7607127037. The cubic root of 1001201021 is about 1000.4001801678.

Adding to 1001201021 its reverse (1201021001), we get a palindrome (2202222022).

The spelling of 1001201021 in words is "one billion, one million, two hundred one thousand, twenty-one".