1001012021 has 4 divisors (see below), whose sum is σ = 1001177772. Its totient is φ = 1000846272.

The previous prime is 1001011987. The next prime is 1001012087. The reversal of 1001012021 is 1202101001.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 540051121 + 460960900 = 23239^2 + 21470^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001012021 - 2¹⁸ = 1000749877 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 (1001012521) 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, 73460 + ... + 86013.

It is an arithmetic number, because the mean of its divisors is an integer number (250294443).

Almost surely, 2^1001012021 is an apocalyptic number.

It is an amenable number.

1001012021 is a deficient number, since it is larger than the sum of its proper divisors (165751).

1001012021 is an equidigital number, since it uses as much as digits as its factorization.

1001012021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165750.

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

The square root of 1001012021 is about 31638.7740122780. The cubic root of 1001012021 is about 1000.3372265988.

Adding to 1001012021 its reverse (1202101001), we get a palindrome (2203113022).

The spelling of 1001012021 in words is "one billion, one million, twelve thousand, twenty-one".