1240021 has 2 divisors, whose sum is σ = 1240022. Its totient is φ = 1240020.

The previous prime is 1240013. The next prime is 1240027. The reversal of 1240021 is 1200421.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1232100 + 7921 = 1110^2 + 89^2 .

It is a cyclic number.

It is not a de Polignac number, because 1240021 - 2³ = 1240013 is a prime.

1240021 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1240027) 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 as a sum of consecutive naturals, namely, 620010 + 620011.

It is an arithmetic number, because the mean of its divisors is an integer number (620011).

2^1240021 is an apocalyptic number.

It is an amenable number.

1240021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1240021 is an equidigital number, since it uses as much as digits as its factorization.

1240021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 1240021 is about 1113.5623018044. The cubic root of 1240021 is about 107.4343135761.

Adding to 1240021 its reverse (1200421), we get a palindrome (2440442).

It can be divided in two parts, 12400 and 21, that added together give a palindrome (12421).

The spelling of 1240021 in words is "one million, two hundred forty thousand, twenty-one".