240000021 has 6 divisors (see below), whose sum is σ = 346666710. Its totient is φ = 160000008.

The previous prime is 240000011. The next prime is 240000029. The reversal of 240000021 is 120000042.

It can be written as a sum of positive squares in only one way, i.e., 144937521 + 95062500 = 12039^2 + 9750^2 .

It is not a de Polignac number, because 240000021 - 2⁶ = 239999957 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 26666669 = 240000021 / (2 + 4 + 0 + 0 + 0 + 0 + 0 + 2 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 239999958 and 240000012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (240000029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13333326 + ... + 13333343.

It is an arithmetic number, because the mean of its divisors is an integer number (57777785).

Almost surely, 2^240000021 is an apocalyptic number.

It is an amenable number.

240000021 is a deficient number, since it is larger than the sum of its proper divisors (106666689).

240000021 is a wasteful number, since it uses less digits than its factorization.

240000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26666675 (or 26666672 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 240000021 is about 15491.9340626017. The cubic root of 240000021 is about 621.4465193163.

Adding to 240000021 its reverse (120000042), we get a palindrome (360000063).

The spelling of 240000021 in words is "two hundred forty million, twenty-one", and thus it is an aban number.