1001331220 has 24 divisors (see below), whose sum is σ = 2194222464. Its totient is φ = 383117856.

The previous prime is 1001331211. The next prime is 1001331223. The reversal of 1001331220 is 221331001.

It is a self number, because there is not a number n which added to its sum of digits gives 1001331220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001331223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1087944 + ... + 1088863.

It is an arithmetic number, because the mean of its divisors is an integer number (91425936).

Almost surely, 2^1001331220 is an apocalyptic number.

1001331220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1001331220 is an abundant number, since it is smaller than the sum of its proper divisors (1192891244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1001331220 is a wasteful number, since it uses less digits than its factorization.

1001331220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2176839 (or 2176837 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 1001331220 is about 31643.8180376515. The cubic root of 1001331220 is about 1000.4435432403.

Adding to 1001331220 its reverse (221331001), we get a palindrome (1222662221).

The spelling of 1001331220 in words is "one billion, one million, three hundred thirty-one thousand, two hundred twenty".