2001223540 has 12 divisors (see below), whose sum is σ = 4202569476. Its totient is φ = 800489408.

The previous prime is 2001223529. The next prime is 2001223547. The reversal of 2001223540 is 453221002.

It can be written as a sum of positive squares in 2 ways, for example, as 1220244624 + 780978916 = 34932^2 + 27946^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001223547) 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, 50030569 + ... + 50030608.

It is an arithmetic number, because the mean of its divisors is an integer number (350214123).

Almost surely, 2^2001223540 is an apocalyptic number.

2001223540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2001223540 is an abundant number, since it is smaller than the sum of its proper divisors (2201345936).

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

2001223540 is a wasteful number, since it uses less digits than its factorization.

2001223540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100061186 (or 100061184 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 2001223540 is about 44735.0370515103. The cubic root of 2001223540 is about 1260.1779248194.

Adding to 2001223540 its reverse (453221002), we get a palindrome (2454444542).

The spelling of 2001223540 in words is "two billion, one million, two hundred twenty-three thousand, five hundred forty".