1001012221 has 4 divisors (see below), whose sum is σ = 1092013344. Its totient is φ = 910011100.

The previous prime is 1001012203. The next prime is 1001012237. The reversal of 1001012221 is 1222101001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1001012221 - 2²³ = 992623613 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1001012198 and 1001012207.

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, 45500545 + ... + 45500566.

It is an arithmetic number, because the mean of its divisors is an integer number (273003336).

Almost surely, 2^1001012221 is an apocalyptic number.

1001012221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1001012221 is a deficient number, since it is larger than the sum of its proper divisors (91001123).

1001012221 is an equidigital number, since it uses as much as digits as its factorization.

1001012221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91001122.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1001012221 is about 31638.7771729566. Note that the first 3 decimals coincide. The cubic root of 1001012221 is about 1000.3372932205.

Adding to 1001012221 its reverse (1222101001), we get a palindrome (2223113222).

The spelling of 1001012221 in words is "one billion, one million, twelve thousand, two hundred twenty-one".