2001221131 has 16 divisors (see below), whose sum is σ = 2515451904. Its totient is φ = 1549691424.

The previous prime is 2001221119. The next prime is 2001221141. The reversal of 2001221131 is 1311221002.

It is a cyclic number.

It is not a de Polignac number, because 2001221131 - 2¹¹ = 2001219083 is a prime.

It is a super-2 number, since 2×2001221131² = 8009772030321838322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is not an unprimeable number, because it can be changed into a prime (2001221141) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 229675 + ... + 238228.

It is an arithmetic number, because the mean of its divisors is an integer number (157215744).

Almost surely, 2^2001221131 is an apocalyptic number.

2001221131 is a deficient number, since it is larger than the sum of its proper divisors (514230773).

2001221131 is a wasteful number, since it uses less digits than its factorization.

2001221131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 467970.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 2001221131 is about 44735.0101262982. The cubic root of 2001221131 is about 1260.1774191671.

Adding to 2001221131 its reverse (1311221002), we get a palindrome (3312442133).

The spelling of 2001221131 in words is "two billion, one million, two hundred twenty-one thousand, one hundred thirty-one".