1001131221 has 12 divisors (see below), whose sum is σ = 1346182656. Its totient is φ = 661757040.

The previous prime is 1001131193. The next prime is 1001131247. The reversal of 1001131221 is 1221311001.

It is not a de Polignac number, because 1001131221 - 2¹⁵ = 1001098453 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1001131197 and 1001131206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001131721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 616791 + ... + 618411.

It is an arithmetic number, because the mean of its divisors is an integer number (112181888).

Almost surely, 2^1001131221 is an apocalyptic number.

It is an amenable number.

1001131221 is a deficient number, since it is larger than the sum of its proper divisors (345051435).

1001131221 is an frugal number, since it uses more digits than its factorization.

1001131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3372 (or 1751 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 12.

The square root of 1001131221 is about 31640.6577207238. The cubic root of 1001131221 is about 1000.3769315714.

Adding to 1001131221 its reverse (1221311001), we get a palindrome (2222442222).

The spelling of 1001131221 in words is "one billion, one million, one hundred thirty-one thousand, two hundred twenty-one".